Elly: That's a good point, but I'm also concerned about how much the frog absorbs stuff through its skin. Most (if not all) aquatic frogs, salamanders, etc. can suffer greatly from being handled for the following reasons: they can absorb soap residues, regular skin oil can block their pores and hinder water absorption, our warmth can cause them to dehydrate... and that's not even counting the dangers of hand lotions, mosquito repellent residues, sunscreen residues, etc. But since, as you pointed out, they have to have tougher skin and be a bit more dehydration resistant, maybe they can tolerate handling a bit more.
Personally I just use gloves. I'm paranoid about residues.