It’s more that they can take them down and put them up using just a few minutes over the span of 24 hrs.
Your options for counter play are
Monitor the location unerring for 24hrs
When he shows up gank every one of the toons he brings after he starts unanchoring the structure. Or to keep doing that until the war dec comes into effect.
Or to again monitor the location unerring for 24 hrs and anchor yours before he anchors his after he unanchored the last one.
Make it so only wardeccable corps can anchor gantries, and gantries cannot be war HQs, so they have to commit an Upwell structure to have a gantry - and a gantry in the process of being unanchored unlocks the planet for someone else to drop a gantry?
Just to add fuel to the fire here, did you know you can just transfer ownership of the Gantry whilst its at war to another corp of your choosing at any point and you dont even have to take the gantry down, the only time you need to bring the gantry down is if you dont have 3 corps you can juggle them around on to avoid wardec timers. Even then its a matter of seconds to abandon your old gantry, then drop another under the new corp. This is expoiting a game mechanic to stop players accessing content they should otherwise be able to.
Adding a unanchoring timer sadly wouldnt stop this issue however, once its unanchored the other alt just comes in and drops next gantry and the process starts all over again. Gantrys should decay, this forces players to put up customs offices or waste their currently deployed gantry.
The high sec poco thing is actually absurd and locks players out of content in the game which is a lot more needed now due to industry changes, thanks to all the new building mats needing more and more PI is required.
#FIXPI thanks @CCP
Now this sounds pretty logical like MTU’s/Depots
How is that different from now?
The way I read the issue statement, the corp was able to invalidate the war by transferring the gantries, costing the deccing corp money without ever giving them a shot at attacking anything. That’s a pretty broken mechanic.
Quote from the Reddit thread:
I’ve had it where the gantries have been the only structure the corp has and once all the gantries have been flipped in the above mentioned method the war ends due to the corp not having anymore structures.
Not quite. The decced corp unanchored the gantries, and a different alt corp re-anchored them; and yes, once the originally decced corp no longer has structures, the war is invalidated.
However, that still doesn’t answer the question of how your suggestion is different to now?
This is already 100% the case.
The gantry itself is conferring the wardeccability. Shift the requirement to a corp must already be wardeccable through a non-insta-unanchor structure to be able to place gantries, and thus have something they cannot insta-unanchor on the line.
I poorly worded the war HQ part, forgetting that the HQ is on the declarer’s part and not a defender item (it’s been a while since I did any war deccing), but the intent of my statement was force anyone who is wardeccable to be truly wardeccable, not able to unanchor all their structures in seconds and transfer ownership to get out of war free.
Of course.
So how does your suggestion change anything?
Or now it is, every Corp that already owns POCOs can suddently become completing immune from wardecs by not owning any Upwell structures (and structuring themselves this way before the patch is released), making the thousands of POCOs in highsec completely immune from attack?
They won’t be able to anchor any more, but all the ones they currently own are safe forever.
Great outcome.
I despise the very concept of the POCO
You don’t like taxes?
You want them all Interbus owned again, or just everyone restricted to using the launch pad and collecting from space (though that makes delivery to planets difficult)?
Of course not. Why did you have to go straight for the worst possible implementation here? I would go about it the opposite direction: people have until the patch to deploy upwells, after that any POCO and gantries owned by a corp that doesn’t have an upwell is unanchored and the planets become available for claiming again.
Or, as the OP amended (#4), decouple them entirely from wardecs. (I don’t think he also meant POCOs should be decoupled from wardecs too, but they would share the same wardec eligibility requirement).
Just like the other non-medium/large/extra-large deployables you would gain a suspect status for shooting gantries and POCOs. Keep the re-inforcement timer on POCOs of course.
While you are at it, reduce the 10M HP and/or the passive shield regeneration.
If you want your cake, you’re going to have to eat it too 
also a good mechanic change for cleaning up abandoned POS towers
Going from the OP wording yes, but the Reddit post was actually a two parter, they wardecced a corp, then that corp owner simply transferred ownership of the gantry (they didnt even loose the investment of the gantry by transferring its ownership!) thus invalidating the first war dec, the second war dec was the point at which the gantry owner had to abandon and pop up a new one in its place instanltly. Now if the gantry owner was really smart he would of had a 3rd corp to simply transfer ownership too and would be able to avoid abandoning the gantry altogether.
Cant say that isnt abuse of mechanics?
I do find it funny that all the whining used to be about the evil wardeccers and now its “oh poor wardeccers”.
It’s been this way since players could own POCOs. Why is it now a problem that needs to be solved, simply because one person is able to outplay his aggressors?
Suck it up and work around that limitation. There are thousands of other planets available to wardec the owning corps of.
Just because something has “always been this way” doesn’t make it any less broken or abused. This way of thinking suits you now because it doesn’t affect you or you don’t care to try to fix it. Its becoming more of a problem now because of what I said earlier, industry changes are requiring more and more PI, not everyone wants to do their PI in low sec or Null, so saying players should suck it up and find a workaround is not a legitimate answer, if players were actually building customs offices on these planets and then putting insane tax rates on them I would actually agree with you, because they aren’t locking content out but that’s not what’s happening.
By placing gantry’s and not allowing players to use the PI on planets then abusing the way players can fight back by allowing them to log in for a minute or two to swap ownership of a gantry and dodge what has taken the aggressive party 24+ hours, plus 100mil, plus the war HQ structure itself to invest in, that is not a case of suck it up, its a broken mechanic.
This isn’t an isolated incident either, there are hundreds of systems with gantry’s and no customs offices too, just idle gantry’s that nobody can remove or deal with.
as previously mentioned. your suggestion of “git gud scrub” has been quashed in the above discussion.
the problem with this statement (as also mentioned in above conversation) is that there currently isn’t a way to work around this. there is no path forward, there is no improvement as a player / pilot that can be learned. not while the mechanics can be abused in the current way
as mentioned earlier when you said this… this is not a solution to the planets that are blocked from use to the entire player base. “get a new house because there is rubbish in the backyard” is just not intelligent
I would prefer that all HiSec customs offices are Interbus again. I don’t see how the POCO adds anything positive to the game, aside from something else to fight over.
No, I’m not dumb enough to wish for customs offices to be eliminated entirely 
I would be happier if this was the case than none at all, as we are now or if removed entirely