I am going on a trip soon. I have 2 fire belly toads and know no one that would spray them every night and day! I am planning on getting a Repti-Fogger. Is the fog bad for them? I would think not .. . but ... you never know!
They'd be fine with the fogger, but honestly if they have a large water dish they don't need to be sprayed every day, they have a tendency to keep their substrate plenty wet on their own. The bigger problem would actually be who will be giving them fresh water while you're gone, as fire bellies are quite messy and fill their water with dirt and waste as soon as they see it's clean.