Personally, I'd be a bit hesitant to let my snake explore, even under supervision, just because what if they get into or under something and you can't find them again? I've heard horror stories from a friend who used to breed corns, one escaped (okay, not supervised, I know) and they found it beaten to a pulp in the couch springs.

I'd be really terrified to have my snake get around heaters too (they get really hot, burns...) and anything that you might not know is there (holes, or ways to get into places that they shouldn't be in).

I just don't think it's a good idea.