I don't think many people realize that bans aren't just to get someone out of your server, but there also to help teach newbs/noobs lessons.
Like lets say that Bob1234 had just bought blockland.
He joins his first server, and starts messing around, spamming some item spawns, and he gets banned, and the reason is "Gtfo noob"
That doesn't help him improve as a player, he'll just wonder why he was banned and maybe come to the forums and cry about it (and just get flamed).
But lets say the admin banned him, and with the reason "Placing unnecessary item spawns"
Bon1234 now has some idea of what he did wrong, and hopefully won't do it again.
Tl;dr
There's a reason box in the ban dialog, use it well.
