It might also be the one time your snake decides to defecate in his water bowl, & then later need to drink. I've heard of snakes getting very sick that way. Chances are
he'd be fine for a week, but no one can guarantee that. Thermostats have also been known to fail & kill people's pets in just a day, while they're at work. Again, the risk
is low, but it's up to you whether or not it's worth taking the chance.