I would be more worried if subliminal messages actually worked.
The only form of effective subliminal messaging is flashing advertisements in a frame. Like coke or popcorn, it makes your mind think about the product and thus prehaps want it.
Aside from that, nothing has been proven to work. And even further, it's usualy a case of 'told what you hear', would you really hear the message if you weren't being told what it was?