As a server owner, I deal with an issue that pretty much all server owners deal with, player punishment. I make banning a last resort when punishing, because the last thing I want is less players on my servers. Muting doesn't always work as a punishment, and kicking isn't serious enough. There is temp banning, but again, less players on the server and it isn't that great of a punishment as the player can just spend their time on another server.

I find sending someone to jail is usually a pretty good punishment, but I wasn't completely satisfied. While the player has to spend their time on the server to get out of jail, they can usually just go AFK. Again, not so much of a punishment if the player isn't really serving their time. I made a better jail.

Why this jail is a real punishment is what I built into it. First, all players are suck on a 1.5 x 1.5 space (since there are iron bars). Second, there are pistons that are triggered by a simple clock around the platform as well as note blocks. All players I have put in this jail absolutely hate the noise the constant triggering pistons and note blocks make. Lastly, the jailers. Mean spirited villagers watch over the prisoner(s) and torment them. Each jailer platform contains three pressure-plate activated command blocks. The last bit is that the jail is land is claimed as a warzone. This is quite painful for players on a server using Factions, as the player will lose power for their faction.

I setup two of the command blocks on each platform to harass the players and one to kill the player. By killing the player, they can't go AFK to reduce their time. Below are the commands I use for the jailers:

/kill @p[997,24,-867,r=3]
/burn @p[997,24,-867,r=3] 50

msg @p[997,24,-867,r=2] When you do the crime, you do the time.
msg @p[997,24,-867,r=2] You break the rules, you get sent here, have fun.
msg @p[997,24,-867,r=3] I get excited when the prisoners scream in pain.
msg @p[997,24,-867,r=3] Keep squealing little piggy.
msg @p[997,24,-867,r=3] What happens in jail, stays in jail...
msg @p[997,24,-867,r=3] Ooh, fresh meat...
msg @p[997,24,-867,r=3] I like my prisoners gagged and helpless... teehee.
msg @p[997,24,-867,r=3] I think I know just what to do with you... teehee.

As you can see with the commands, they effect a very small area inside the prison. This makes it easy for staff to maintain the jail and make changes to the command blocks without having to worry about being effected. The command blocks are also easy to get to as long as the jail is in the air. I have found this to be a very effective solution to deal with players breaking the rules, though some of the non-rule breakers tend to enjoy this (a bit too much in my opinion). I hope this build will help your server if you use it.