Another Interesting Home Game situation

What are the rules on this? In Supersystem, DB talks about if he has A-A and a player is betting into him, he will show the A-A and try to get a read. I assume DB was talking about a cash game, not a tournament, and was heads up.

I have used the trick myself, like when I had an Ax with x being a low kicker. Why you would show with the nuts is beyond me, maybe he was flustered/excited. It was a big hand.


I would really like to know the rules, officially. Have they changed since Supersystem? If so, why? Collusion?