A system that kicks the player with 3+ consecutive letters in their names instructing them to make a new character without the letters in the end would mitigate the Jr. bans.
Otherwise, a player could be disabled (stone, webbed, frozen, unable to use chat and cmds) and constantly warned by the server to change their name.
Maybe write following text above Ban in the red box (stroken through text = old text): (Do not hestiate to correct me)
This Ban might be a mistake
There have been reports of users getting this link who are not Jr. If you are one of these people, you are encouraged to appeal so staff can investigate.
If you are getting this ban by mistake, rejoin the server with a name with the following properties:
containing no more than 3 same consecutive characters