It seems to be a habit that WW players leave their E on, revealing their location, and even if the enemy is dumb enough not to look at the minimap showing clearly where WW is, they'll still know that he's nearby. Also, I don't see how WW can easily get ganks off post-level 6 if his ult is cheesed somehow by the enemy.
Enstraynomic - League of Legends
TheEnst - Starcraft II