Should be banned from using
So list of crazy commands i remember:
/kill
/op
/attribute (we can put limits)
/effect (we can put limits on how powerful the effects can be)
/gamemode
/gamerule (maybe just put like area limits, he can only influence a certain area
/locate (only places he has seen, just to know the coordinates)
/tp (he has to know the coordinates of the place, but he can tp to anyone)
Now should we ban the strongest command in the game? /execute ?
example: Exploding snowballs
/execute at @e[type=snowball] unless block ~ ~-1 ~ air run summon tnt