It really takes a long time to make the throws smooth and have both look exactly the same, so if you're fairly new to 3CM, most likely there's some big tell. Also, when giving demo's (IMO) of gambling games shorter is better.
Some people think showing every move ever invented is the way to go, but it gets boring and they sometimes give it away. A nice short routine showing the scam working and done. Someone like Pop could do a long routine and keep it interesting and not get caught, but he's a rarity.

On the street, the operator wants to look like a loser--someone easy to take. The sucker only gets to bet when he puts everything on the line, and it is the first and only time the hype is made.

In an exhibition, the operator has to win every time, or the spectators will laugh at him and lose interest. The point of the exhibition is to prove the spectator can be beaten. The point of the real game is to take the money. The spectator isn't even allowed to bet except once.