I've been leveling a hunter recently, and whenever I'm in a LFD group that's about to face an inevitable wipe, I get a safe distance away and use Feign Death, then teleport out of the dungeon and back in to guarantee my survival, but a lot of the time someone in the group calls me out on it, saying it's not fair that I didn't die. I've seen rogues get the same thing for Vanishing and Mages for using Invisible. I don't see why that gets people mad though. If you die, you pay a repair bill, whether or not I die has no influence on how high that repair bill is.
I can see how in a Raid this might be a problem, causing me to possibly have the Sated Debuff during a part where Bloodlust would be useful, but so far this has only been in simple 5-man normals...so what's the problem?