Ok, so you open up a new service. People drop their dogs off to be walked for them.

Then, that service advertises that you can volunteer to walk a dog.

So now you got people paying you to walk a dog. They show up, and a blind person accepts the dog to be walked. And you in turn get someone else to walk the dog for free, with the promise that you get to hang out with a dog for a few hours.

And then, at night, the blind people who work the front desk get into a boxing ring, and you run a gambling service on which blind boxer will win.

So now when the people come to pick up their dogs, you have the blind guy ask if they want to buy a ticket to see them in a boxing match. And because they're blind, most people would feel bad, and buy the $20 admission. Even if they don't attend.

Now, my only concern at this point is figuring out how not to pay the blind boxers. If I can do that, you'd have a business with no labor overhead, and 100% profit.