I don't understand how someone could leave an infant sleeping for hours without checking on them.
I wouldn't leave a school-ager sleeping that long unattended.
I know its probably easier for me because Im in a center and all mine are around the same age and nap at the same time, but my sleeping kids are never out of my sight longer than it would take to run to restroom or go get something. Even then, they're not out of earshot.
If our job is supervise and take care of children, I don't understand why people think that doesn't extend to naptime.