From the 3.11 patch notes: Hostility Updates: Acquiring a missile lock on a target is now considered a hostile action against AI and other Players allowing them to attack the person locking them without being the aggressor. When you say "Rules of Engagement" to most people, they will either think of a bad rom com (which means they're probably not playing Star Citizen), or they will think of something along the lines of "do not fire until fired upon". Real military ROEs are of course more complex, and depend upon the situation and theatre. But for a game like Star Citizen, "do not fire unless fired upon" is a reasonable starting point for self-defence against an opponent who has not already been declared an 'enemy'. So what is this stuff about missile locks (not launches) being regarded as a hostile action, allowing hostility in return? It's not very intuitive, and seems wrong to me. Threatening another ship with a missile lock is not the same as attacking them, and shouldn't be treated as such. To prove my point, I refer you to the most authoritative source on all matters of fighter combat, Top Gun: Edit: After discussing this in the thread, I think I should expand upon my position a bit: Firing on someone who has locked missiles on you should be a legal grey area. It should be something which is not strictly encouraged, but does not necessarily cast you as the aggressor either. There should always be some amount of uncertainty about the legal ramifications for firing first if you are being directly threatened. This would force players who are threatened with a missile lock to have to decide between doing the expedient thing (firing first) or following the letter of the law ("do not fire until fired upon"). That, to my mind, represents good gameplay.