not only can they join the mission battle to gank you, but they can join well after the normal 5min timer for NPC fleets in open world. last night i had 3 tricom's join a mission i was in 9 min after it started!!! really? and again, friends nearby cannot join because of 1, i am not in a party with them, and 2.. even if they were in a party with me it has been MORE THAN 5 MIN!!!!
please fix this, if you are going to limit what can join on the players side, also limit what can join on the NPC side of a mission battle, this is being exploited right now to gank people without any chance of retaliation.