Funny, I haven't thought about UL since I was a kid. Do many consumers look for a UL stamp, or is it used more for legal defense if the device actually does malfunction?
The American Dental Association is another example. I do look for ADA-approved toothpastes.
I believe it ends up getting enforced at the retailer level; most major chains will refuse to purchase Christmas lights that are not UL listed, so you can be reasonably sure that the cheaply manufactured lights you purchase at Walmart don't burn your house down. They also seem to be providing education [1] and revising their standards [2] to discourage particularly ill-advised appliances such as electric turkey fryers.
The American Dental Association is another example. I do look for ADA-approved toothpastes.