Just a couple points base on "Robert's Rules of Poker", the standard on which most card rooms are based (although house rules can take precedence in certain circumstances).
The following actions are improper, and grounds for warning, suspending, or barring a violator:
Telling anyone to turn a hand faceup at the showdown.
My Note: Turning cards up did not even enter the picture until TV ratings and hole cams came into play. This practice was invented in the US for tournaments and is widely adopted in home/private games. And if this is a cash game, you are not required to turn up cards at showdown unless a house rule prevails or you lay claim to a pot.
1. Management reserves the right to make decisions in the spirit of fairness, even if a strict interpretation of the rules may indicate a different ruling.
1. To win any part of a pot, a player must show all of his cards faceup on the table, whether they were used in the final hand played or not.
5. Any player who has been dealt in may request to see any hand that is eligible to participate in the showdown, even if the opponent's hand or the winning hand has been mucked. However, this is a privilege that may be revoked if abused. If a player other than the pot winner asks to see a hand that has been folded, that hand is dead. If the winning player asks to see a losing player’s hand, both hands are live, and the best hand wins.
6. Show one, show all. Players are entitled to receive equal access to information about the contents of another player’s hand. After a deal, if cards are shown to another player, every player at the table has a right to see those cards. ... If only a portion of the hand has been shown, there is no requirement to show any of the unseen cards. The shown cards are treated as given in the preceding part of this rule.
Anyway, just my $.02. Actually, I guess it was more like a $.25.