Hello, I believe that using a rewards system like you described would work in convincing people to purchase and use their own cups. In addition, making the cups collapsible would help in this also since it is more convenient to carry around this way.
Hello, This cup concept seems very good. The example images show that the cups are thick enough to prevent burning your hand with hot beverages. However, would there be any concern of the cup absorbing the liquid and leaking?
Hello, I believe that limiting use of plastic lids is good, but I'm not sure that your solution is a good way to do so. It feels as though if something knocked into your drink, it would still spill. Or if you are walking and swing your cup accidentally it would spill.