Today I was in a random heroic with a Moonkin constantly going AFK and a tank with the same HP as me (Rogue). Needless to say, it didn't go well.
Tank decides to do achievements rather than just clear, we wipe horribly, I decide to leave as raid is soon and 2 badges isn't worth the repair bill.
I attempted to teleport out but couldn't while dead so I dropped group and released, ran back and zoned. No more group, no LFG Deserter debuff.
TL;DR version.
1. Random Heroic group suck?
2. Die
3. Drop group
4. Release spirit
5. Run back and rez
6. Zone out
7. ???
8. Profit (and requeue immediately with no deserter debuff)
Is this game breaking? No, of course not. Is this intended? No, otherwise there would be no deserter debuff in the first place. I hope this helps you get out of awful PuGs and on your way to badges. Good luck!