Students are getting into each other's player cards
Students now pick a secret sticker as well as a name, and three wrong guesses lock that device for five minutes.
This is fixed. Each student now picks a secret sticker as well as a name. Three wrong guesses freeze card sign-in and tickets on that device for five minutes, so a student cannot guess their way into a classmate's card. They can keep playing while they wait.
The freeze clears on its own. See A student says they're locked out.