If there's a question about your friend's ability to care for Cobalt for 10 days, I would definitely reconsidered leaving Cobalt in her care.
Perhaps your vet, local humane society, or reptile pet shop might provide a list of chameleon keepers in your area willing to care for your ward in your absence? Cobalt would probably do better in the hands of even a less-than qualified petshop owner, versus your friend, I think. If something WAS to happen to Cobalt in your absence, I don't think you'd want that to get in between your friendship.
I remember caring for a friend's cat while they were away for 2 weeks. The cat REALLY missed them, got depressed, and ended up dying. The necropsy showed that the cat died of feline leukemia (the cat had it for a number of years, but it never manisfested itself. It manisted during their absence because the cat was so depressed). Nothing that I did wrong, and my friend didn't blame me per se, but I could still feel the resentment towards me.
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Victor Gomez
gomezvi@yahoo.com