Trust me, in San Francisco, anything goes in terms of fashion. Just make sure that you look like you tried to look good, and you intended to look just as you do. Nice jeans, worn nicely, can work so long as you work them. The bay area is pretty flexible.
If the particular club has a no jeans policy, you can be pretty certain they ll enforce it. That said, it depends on the specific club... that information might help a bit. But yeah, as a general rule, a no jeans dress policy means just that and there s no sense in testing it (what s the point? A profound statement against jean discrimination? *boring*) unless you really don t want to go to the club. So, just replace them with slacks and you re good. Why bother going to such a club if you re not gonna really dress up for it? There are a million other clubs where people dress like **** and you d be more than welcome to wear jeans there.