i don't think this is such an absurd idea, I think its better than not letting him go in the tree at all and much like chameleons get use to being handled, he'll probably get use to it...the only concern i'd have is of him getting tangled and stuck in direct sunlight but since your checking very often thats not the biggest concern....you have to accept that there are a lot of jerks on this website, for someone to bark GROW UP YOU DON"T WALK a chameleon like a dog...that is just a jerky thing to say, chameleons are owned by a lot of people that are like that, but most of us just like to watch things thrive...i for one don't see any problem with the idea except there is a better idea, which is to build a very large frame out of one by 2's (extremely easy just make sure to get plans and make exact measurements because its easy to get mixed up once you start) and then stapling pool screen around it and placing a 30 dollar ficus tree inside it, problem solved
but i will admit the thought of a leashed chameleon is kind of rediculous, i'm just not going to jump all over you and be an ass, like people on this forum love to do