It's very questionable no matter which way you look at it.
Stealing four $25k chips seems more logical for a cheat (why not go for more then one chip?) unless he feared he wouldn't get away with taking that many but thought he would be okay with grabbing just one.
Either way, we don't know what was going through this guys head. If he really was taking it for a souvenir or took the chip with intent to cheat but they can't prove he ever did then let this be a lesson to the guy for the future if he is cleared.