Andy: Several things play into this:
1. As DCJ001 said it is a poker game MADE FOR TV!!
2. All of these players are INVITED to play by the Producers of the show. If you or I wanted to play we would be laughed out of the place.
3. At the stakes they are playing for the producers allow them to mess around with the rules somewhat to make the game more interesting for the TV audience.
4. Almost everyone of these players are, and I don't mean this in a derogatory way, "degenerate gamblers". They are ALWAYS looking for ways to create ACTION.
5. For most of them, Poker played strictly by the rules, is BORING, BORING, BORING. They need to stroke their need for ACTION and tweaking the game with Rabbit Hunting, Running in Twice, Insurance Bets and Proposition Bets are ways to satisfy that need for ACTION.
DO NOT look at these games and think just because the "Big Boys/Girls" do it, that it applies to the rest of us. IT DOES NOT!! At least not if you want to play 'strictly by the rules'.
Chet