Try thinking of it like this. Let's say you were offered the option to pay X and also help clean the dojo, or pay X+Y and the dojo hires someone to clean up. You could also think of it this way - at a fast-food restaurant, the patrons are expected to throw their trash away as they exit. They don't have to do so. No one will run after them if they don't. But if no one cleaned their own table, the restaurant would have to alter their business model, hire more people, and prices would go up. But ultimately, I think buying a 'good' (like fries and a shake) is not like buying a service (like training). You pay to be taught - and you'll be taught if you show up. However, the instructor doesn't have unlimited resources. Students needing one-on-one or desiring advanced training require more effort, and that's a limited resource. So it is not (IMHO) unreasonable for an instructor to limit some of that to those whom he or she thinks will be best able to receive and implement it. Students who do things like exhibit a good attitude, who are enthusiastic about training, who give their best effort, help others, and yes, even pitch in to tidy up the dojo after class might be good indicators of the kinds of people who are most deserving of that extra bit of effort by the instructor. That's how I look at it, anyway. I don't think I am being made into slave labor by pushing a mop around for a couple minutes at the end of class, or emptying out a trash can.