Well the idea isn't that bad, but people seem to think if one or two forbidden things are possible then all of a sudden everything that was forbidden is possible. You'll end up with Amsterdam.

Also problematic is the fact that in a lot of countries everything is outlawed so they might go looking for hard drugs where soft drugs are being sold. I've seen enough tourists seen thrown(1) out of a coffeeshop for asking any kind of hard drugs. What they don't find in coffeeshops they do find with street dealers.

(1) yes, flying