The reason why you can’t have players doing this job is because they don’t want to do this job. Most of these people just want to turn on a mining laser and go AFK. Of the few players left who are willing to engage with the game, most wouldn’t be willing to perform this function because it wouldn’t pay much, if anything at all. Think about it: you can’t have a situation where it’s possible to generate more money from police work than the sunk cost of the gank itself. For example, you can’t pay someone 10M ISK for destroying a 2M ISK ganking catalyst; if you did, then it would be possible to game the system to generate infinite money. But the whole point of ganking is to minimize costs while generating a profit, so gankers will always be flying cheap, expendable ships.
The only way to create incentive for players to perform police work is by doing it on a mass scale. For example, if we tie high-sec PvE activity profits to a global crime index, then players might be motivated enough to contribute something to the effort, or accept that they’ll be making much less money. But that doesn’t eliminate the free rider problem, or the fact that most of these mindless worker drones are just going to quit the game if they start making less ISK, instead of trying to address the underlying issue.
The mechanics are actually the easiest part of the equation. Give all ships a distress beacon, and possibly a short-term invulnerability window similar to what Rorquals have (otherwise no player cops would ever get to the victim in time). We actually have something like this in the game already, in the form of the assault damage control. Activating such a module requires manual interaction with the game too, so all the AFK people are going to die just as they always have.
But like I said, you’re simply not going to get many takers to take on policing jobs. Most players are terrified of anything PvP-related. If you don’t believe me, suspect-flag yourself and fly around, even if in a relatively weak ship like a normal cruiser. Unless you run into a group of high-sec PvPers (which tend to stick to specific areas), no one’s going to touch you. In fact, most players will actually get away from you as quickly as possible (miners will warp out of belts when you show up suspect-flagged, I’ve tested this). Kind of like this:
And to add one more thing: most players, especially those who’d be interested in policing the criminals, aren’t of the good-at-PvP type. You’d have a bunch of “durrr, Sarge? I dun lost da boom-boom pin again” types trying to be cops. So most of the victims would still die, and these cops would die too, unless you give them some sort of handicap (e.g. invincible ships with kill triggers, just like CONCORD today).
but we got it the good old days.