For those who use HUDs, it would not be dangerous for the system to pass information from their cards online to other players.
As you know if you use HUDs it will be with you at the time of your game, as other people may have the same system, so there is a possibility that your cards are being shared.
When the player bluffs, he or she guarantees that the system will not pass the information of his cards to the other, or when he has a pair of AAs, the same system will not give the information to the other user to fold.
Even using the HUD no one can trust 100%, this is because the game is online, and online systems communicate.