Video poker strategy sheets - OK to use in a casino?

[roundcat]

Do most casinos consider it OK to refer to a video poker optimum strategy sheet while playing video poker? I've done it and no one has said anything, but I feel vaguely uneasy, like I'm cheating or something. Since blackjack strategy cards are acceptable to use at the blackjack table I'd assume video poker strategy cards would be the same, particularly since there's not a lot of +EV (if any) even with perfect play.

But still... I'd like to hear what others think. Is it something casinos frown upon, or couldn't care less about?