Because, you monkey, You're not completely invisible. This is from a blue post on, I believe, page 6 of the Hunter Preview comments section:Originally Posted by Valdun
"It is *not* stealth. Your enemies will never wonder where you are. We're trying to use the new Cataclysm water effect to put a shimmering PREDATORy visual on you. It's protection from ranged attacks and it gives you some combat bonuses, but it's not like Shadowmeld or rogue / druid stealth where players can't find you."
Basically, you become the Predator, and you sit in the Lumbermill waiting for someone to arrive to cap your flag, then Cobrashot that bitch and send your pet in to finish him off.
Alternatively, if you can use it in combat, camo and then run like a bitch. Fun spell is fun.