Big players can see your stop loss orders, and everyone else's, and it's worth their while to sell agressively down through very thin bids above your stop loss, and grab your shares. Full-time traders at the hedge funds consider it part of the job requirements - low hanging fruit.

True enough, if your stop losses are way, way down there, they probably won't get picked off, but you need to move your stop losses assiduously with major market moves. In volatile stocks like these, since you have to be on top of it anyways, you might as well not let them know where you will sell.

Suit yourself.