Do Now

No because  that is not harmless because he should not use what hes good at and use in for bad things.  But also he shouldn't have don that just to show his smarts.  He should not care if other people don't believe him. But that was also not a harmless joke because some one that  does not go to that school or a parent that wants to enroll their child sees that and then they say no well never mined thats not a good school to put my child in. So that was not a good idea for him to do that.