A woman was severely burned when she fell asleep in a tanning bed with a defective timer.

That part about burning from the inside out sounds an awful lot like a popular urban legend. Though maybe this is a true story in which the woman believes the urban legend.

http://www.snopes2.com/horrors/vanities/tanbed.htm

I agree. It's a UV bath, not a microwave oven.

It could be worse. A few people a year managed to do the same with a perfectly functional timer. They're under some illusion that that the tanning bed avoids all the hazards of conventional sun bathing and keep going back for more until severe symptoms make them realize they're slowly killing themselves. The delayed effect can let them do a lot of damage before they catch on.

To my mind a safer design (for upsupervised home use) would be a system that requires a minimum period of non-operation after a session based on the length of the session. This pause would give the dolts a chance to realize they're already well done before doing more damage.