It can be *quite* obvious to a helicopter flying over. Also, if the grow is in eyeshot of ANY neighbor you're gonna be in deep shit. I hope the roof is flat. I've heard of it being done, the person lived out-of-the-way of neighbors and helicopters weren't a problem...there were some heat issues due to the dark covering on the roof. All in all, not the best idea, lots of possible complications. Really isn't worth the stress unless security can be ensured.
