Responsible Wish Fulfilment

It was a sunny, unseasonably warm November day here in Toronto, so my "little brother" Alfredo and I took the soccer ball to the park for a little one-on-one. Over post-game pizza (he trounced me 12 goals to 6) he had lots of questions about cancer and my treatment options (he's been following the blog -- hi, Alfredo!). After I attempted to explain all the complicated factors involved, he decided that what the world needs is a wish machine. However, if the greedy attempt to take advantage by wishing for, say, $1 million when they don't need it, the machine responds with "not approved." If you wish to cure cancer, it replies "approved" and carries out the wish.

An excellent idea, I say. Can someone get busy inventing such a device, please?