I make an offer, they accept it or decline it.
When you "make an offer" to someone who looks up to you as an authority figure, it has an exaggerated effect. An uchi deshi is not a slave, and even the ones that receive a stipend can only be expected to help doing regular maintenance around the dojo. As soon as you have your uchi deshi making you money by waiting tables at your restaurant or cleaning your rental apartments you are taking advantage of your position of authority to acquire free or underpaid labor, a significant violation of another person's human rights. Just because that person agreed to do it, even if they knew the circumstances, does not make the situation acceptable.