White bag on drain pipe in restroom?

Question

In most of the mini-marts and gas stations I've been to lately, there is a white bag around the "J" pipe that goes from the sink's drain into the wall. The clerks I've asked have no idea why it is there. I was hoping a small business owner would know. I live in California. Your results may vary.

Added afterward: It isn't broken. The "bag" is cloth or canvas, quite thick and designed for the purpose. I should have written that in my Q.

With only two answers, I called a commercial plumber. After working my way up through three people, he told me that the Americans with Disabilities Act demands them just in case:

1) Someone runs VERY water for a long time, which drains out;
2) The drain pipe heats up;
3) Someone in shorts in a wheelchair brushes his/her knee against the scalding-hot pipe and gets burned.

Sounds stupid, but plumbers don't pass laws; lawyers do.

Answer 1

I believe most often they are "padding" to protect small children from whacking their heads, and also to protect against vandalism by customers.

Answer 2

Maybe it means it's broken and not to use it, so they put a bag over it?! I know where I live, that's what it usually means.