did someone break the rules on your server? i know the perfect punishment for them. just make a 3x3 pillar out of bedrock 256 blocks high with the middle hollow. then put 256 blocks of cobweb in the middle all the way down. and somewhere along the way(say 73 blocks from the bottom) put a sign with a word on it. then drop the offender down into the cobwebs from the very top and after they have fallen to the bottom they have to tell you what the word was. if they come up with the right word then they are forgiven but if they dont then ban.
an even better idea would be to put signs with the server rules written on them all the way down and hidden among the signs is the one with the word on it and they will have to read the server rules on every sign again and again to catch the word.