adjl posted...
To elaborate on this in a way that's actually helpful, in Texas Hold 'Em, 3/5 of your hand is comprised of the cards on the table. If you've got a royal flush, that means the three cards on the table contributing to your flush are the same suit and therefore the only possible royal flush that can be made with them is the one you've got. Somebody else could have a straight flush in the same suit, but it's going to lose to yours in value.
Actually, there is a way to see 2 royal flushes in Texas Hold'em, and that's if the royal flush is in the house, so literally every player gets a royal flush