I want to place a regional buy order on an item, but the reason I don’t is because I am afraid someone might sell to my buy order from within a locked station.
Is this possible? Or are there measures in place to prevent me from buying inaccessible items on the regional market?
You can only fill a region-wide buy order at an NPC station or the Upwell Structure it was placed at (if it was). There is no danger of someone filling it from a station you don’t or won’t have access to with the exception of if you are locked out of the original Upwell structure you placed it at.
Even if it did happen though, you can also always use asset safety to retrieve your stuff in 5 days. But it won’t in general for region-wide buy orders - everything will be in NPC stations or where you placed the order.
No problem! In case you didn’t consider it, your region-wide buy order can also be filled in an NPC station in lowsec or a highsec pocket behind a lowsec system. For small items this doesn’t really matter much if you are comfortable moving through lowsec, but for large bulky items, you will require specialized ships to move things safely or use contracts which can cut into your bottom line.