I've noticed, whenever someone says "Ignore this post", it gets a high post count. =P I guess everyone puposely don't listen to people, and do the opposite.
Mega, it's the same reason as why you don't tell a child "don't you try to take a cookie from the cookie jar". If you call attention to it by saying no one can have it, or that you don't need to pay attention to it they pay attention.