Very first day of kindergarten

So, we are in trouble, this is the story from Sam's first day of kindergarten:

Me, "Did you make any new friends?"
Sam "Just one silly friend."
Me, "What did you do with the silly friend?"
Sam, "There is a sign on the bathroom door in our classroom and when someone is in there it says, "yes" and when someone is not in there it says "no", so whenever anyone was in there we would switch the sign and then other kids would just walk in and everyone would see them going potty."

Yes, DAY 1 of kindergarten, not good, not good