Random unsolicited FC invites from people who don't check my search info first. Especially those who send two invites (by sending one almost immediately after I reject their initial invite). The lack of an FC tag on my name isn't a fluke or just me not having found "the right one" yet. It is a conscious decision to not join any FCs because I am a chronic server-hopper. Fortunately, the closer I am to endgame areas the less likely I am to receive an FC invite.