Have you ever understood why you can't play roulette to clear your deposit bonus? I've never found the reason for this explained in their terms and conditions. Have you?
That is something that I have never actually stopped to think about before, but it's nice to learn something new everyday. I doubt that most people bother themselves with this at all, though.
That makes a lot of sense but I think for most people the bonuses can be a little too enticing and hard to resist. I personally fell for this a few times in the beginning.