So what's up with this?
I talked to several waiters and waitresses in SF last weekend and it seems that it's nothing more than a health savings account that the customer gets to fund.
The waiters are not exactly right. It goes to the city, to pay for a program to provide health care to the uninsured.
More info:
http://www.sfgate.com/cgi-bin/articl.../BAEKV6KF2.DTL
http://www.sfgate.com/cgi-bin/blogs/...entry_id=28281