In this particular case, a level 70 Warrior (posting on his level 42 Mage alt) claims that he forgot to loot the Vial of Eternity from his guild's recent Kael'thas kill. He filed a GM ticket, and they refused to grant it to him, stating he should just go kill Kael again for it. Embers, the alt, goes to the forums to ask for this vial instead. EU Game Master and Customer Service Rep Xaldavan joins the show pretty quickly, asking for some necessary information to help him (her?) investigate the situation, even offering to give him the quest item if his claims are accurate.
As you can guess, they weren't accurate at all. In fact, the Warrior left the raid an entire hour before Kael'thas was actually killed. In the middle of a trash pull, too! You would think people would know by now that trying to scam a GM is silly. As Xaldavan said, they can see everything. Some of these people are very, very lucky that Blizzard's GMs tend to be merciful about these sorts of things.