Ethical/Rule question re: showing your cards in live games/tourneys

[Mayhem]

There have been times, especially in live tourneys when I've wanted to make a big bet and just show my cards to the guy I'm heads up with to get him to fold - like when there is a big amount already in the pot, and I'm 90% sure I have him beat and do NOT want to lose to a suck out.

What is the general feelings and rules on this? I guess I can find out from the casino floor what thier policies are... but even if they give you a 10 minute penatly in a tourney sometimes I think it may be worth it, especially late in a MTT when you are short stacked.

In a ring game, a play like that may win you a big pot on the spot, which could mean significant real dollar implications.

I'm curious as to everyone's thoughts on this, thanks.