In reality, the RNGs used by online poker sites come as close to real randomness as possible, simulating random outcomes by running through millions of card combinations per second.

PokerStars has one of the best bot and collusion security prevention teams in the industry. They take this very seriously. But of course whenever there is money involved in anything in life, people will try and cheat. So it doesn't stop people from trying to run a bot on PokerStars.