YOU WILL BE HUNTED DOWN!
<note warning>SPOILERS, MATE</note>
If you let your exp bar fill up too far1) someone from Joe's Dojo itself will sneak up on you in an Outpost and bash you over the head. Then the Dojo will whup your ass for not coming to see it, or even writing every once in a while.
You can decide if you want to get the jump on the next master also when this happens, to avoid further flying blunt objects.
Truancy can be a great way to bunk off the normal humdrum existence that infects the lives of the normals on the island. It is also cool as all of the cool kids do it. They also smoke cigarettes and drink cheap cider.2) Try running away from NewHome and visiting CyberCity 404 for a while. It's lovely up there.3)
Using advanced techniques, one can rack up enough experience to defeat all of one's masters in 14 consecutive fights. This is known as (a) “Dojo Fury” and it is universally acknowledged to be super fucking rad.
The Greasemonkey page has a couple great scripts for tracking Truancy.