For some here who seem to question whether revealing cards in this manner is an infraction or not, this is what "Roberts Rules of Poker" stipulates. These rules were compiled and amended many times by an industry veteran, Bob Ciaffone so as to standardize rules from one poker venue to another. He is a rules drafter and consultant for the industry. Listed under Poker Etiquette -
The following actions are improper, and grounds for warning, suspending, or barring a violator...
Revealing the contents of a folded hand before the betting is complete. Do not divulge the contents of a hand during a deal even to someone not in the pot, so you do not leave any possibility of the information being transmitted to an active player.