For those struggling with getting banned during full marks, if you keep an eye on Hogwarts Mystery reddit and/discord, you can find out when a full marks event is going to be released, and avoid logging in completely during the event. You can also try staying completely logged out of the game until maybe an hour before the full marks event is over if you really want to get the prize, and it's usually pretty easy to get 1st place without being banned and without cheating because you will usually be put in a relatively inactive group when you wait to log in until the event is almost over.