Short and simple answer: You transform the design into a website/app, get your money and go pay some bills
The question is tantamount to saying that if I go shopping, that the shop owner asks me how I made my money before allowing me to spend it. They could care less. All they want is that you use real money to pay for your goods. Likewise, rather than question the morality of the designer, code the site, get your money and move on to another site.