Blacklists are a waste of time. It's too hard to communicate them, it's impossible to keep them in sync and up to date, and most importantly - there's never any proof. If you want to get into the endgame stuff and you care about loot, get into a guild. At least there if somebody Ninja's, they don't get a second chance.

Damn the game is changing. i remeber back in the good ol pre TBC days, you got PUG raids and instances and there was like 1/1.000.000 that there were a ninja in the party. now theres even distrust in normal non-heroic instance with blues at the line and fear of ninjas. kinda sad that the people that play the game has changed the atmosphere so much, that you expect people to steal loot from you instead of being happy that you got something useful in a instance for once. ah well, im still gonna be back when WOTLK hits. just have to dust of all the old ingame friends to go raiding with. but ask blizzard for a trust rating system ingame, so people that have ninja items, or in your case tried to sell it for ingame gold, gets busted and all people on the server knows his/her name. Like the servers most stupid players top 1000

Report him and move on to the next raid, remember you can report someone for whatever reason you choose Also don't pug, please for the love of god don't even condisder pugging when WOTLK hits, your heart will be broken