Maybe we can use poker face in a limited time, so we do not have to feel tormented using that.
But for a pro poker player will figure out the other way to give a trick to their opponent, so the opponent will not know if they have a good card.
Using those things can help us be undetected by the opponent, but we should be aware of the rules because sometimes, the casino can use that rule.
But it is hard to be unpredictable in a poker game as we can meet the pro poker player, which is not easy to trick them.
Yeah if the tournament is being broadcasted on TV then it is very unlikely that you can fully cover your face. It will always be a tradeoff between entertainment for TV purposes and playing the best and most unpredictable poker we can do. The problem when our cards are being broadcasted is that all other players can watch the feed 30 minutes later and see if we were bluffing or not. This changes a lot for us because we aren't so unpredictable anymore. Since the pandemic a lot of more online tournaments are being broadcasted aswell, which takes away a big part of our strategy in poker to remain unpredictable.