In the past admins (and I'm talking years in the past) said that not every enemy group member must be given an engagement notice or RPed with before engagement, and (although this was more rare) even that not everyone in a group must RP before engaging, as long as the group leader, or members of the group does. It's even been said that anyone who is onlooker in a RP fight (even if they're not grouped or allied with other participants in the fight) is fair game to be shot at without talking to them first.
I mean imagine a group fight... and you have to RP with every single enemy before entering it, including those who arrive late. It's impossible and useless except if you're a rule lawyer type.
Also, I think game mechanics were specifically engineered so people can be shot easily after disconnecting.
