In a live game, can they sure, is it technically allowed no. It's 100% cheating. Will they be caught in most cases no. In cases like with videos being there, will they be caught, probably not, especially if they don't show, videos are on delay. Potentially they could review footage and deem collusion and withhold prizes I believe if it consistently was happening.
It's a hard one to be honest as the person could say they misread their hand, which happens genuinely for many people. If it happens once it's probably not going to have anything happen, but if they keep doing it yeah I could see some penalties and action being taken. Could a floor staff do something there and then, maybe, but will they probably not as it's extremely hard to prove at the time.
If they reviewed footage and found a consistent folding of the nuts to a single player, sure collusion and something will likely happen, but isolated incidents, very likely nothing will happen.
What you're referring to is basically dumping chips to a player. It's a cheat where the 'stronger' player of the team gets chips dumped to them by others players on their team.
To your question of pretending to set up a bluff, what value does doing this honestly have? Chips will have way better value, especially seen as you're mucking without showing, so literally zero value, plus incredibly silly to do to a random person you're playing against. If you're genuinely thinking of mucking the nuts as a strategy I don't think you should play poker to be honest.
Please note I'm talking about mucking the nuts, i.e. the best hand possible on a board. People can and do fold the best hand all the time to weaker hands, bluffing being a fundamental part of the game. But to muck a winning hand when you see the opponent has a weaker hand than you is just incredibly bad and silly unless you're actively cheating with that player.