Won't this just encourage users to create more garbage?
If I am in need of wifi, and I have no garbage, I would need to create garbage (buy a juice, snack etc) to get the wifi, even if I wasn't thirsty or hungry
"When people drop paper into the water she hides it under a rock at the bottom of the pool. The next time a trainer passes, she goes down to the rock and tears off a piece of paper to give to the trainer. After a fish reward, she goes back down, tears off another piece of paper, gets another fish, and so on."
If I am in need of wifi, and I have no garbage, I would need to create garbage (buy a juice, snack etc) to get the wifi, even if I wasn't thirsty or hungry