Here's my take:
to be an exploit it must give the player a benefit of some kind.
The relog trick only keeps you from getting destroyed. It doesn't help you win. A quickie fix would be to have peeps who logout on a PvP match get dumped from the match and not automatically readded when they login.
AFKers deserve to be shot repeatedly. I've had LT chars challenge my VAs to PvP then go AFK and not respawn when I KO them.... it's lame and dumb. And don't get me started on the dimwits who think their LTs should be able to go 10 rounds without getting their butts KOed repeatedly.