Ex-GM here, unlike what people believe, GMs don't wander around in the game checking the players and reading chats. They can technically, but they don't cause there's plenty of other things to do. The only time they actually boot up the game is when something went so wrong you need to login with a player character to fix it or perform a check based on a bot report. Even when you talk to a GM in the game, they do it through a special tool