I agree with others that in the future you should bring your bike in. Living in San Francisco I'm very uncomfortable locking my bike up anywhere and I'll ask to bring my bike in to stores and appointments. I've never been refused.

As far as the drunk vagrant, that sucks! Since this isn't the first experience you've had with aggressive unwanted sexual advances it is no wonder you were uncomfortable. I would suggest that you sign up for a women's self defense class. I'm not suggesting that you beat anyone up but it will boost your confidence which overall will make you a less easy target. Again though, I'm so sorry that happened to you and I hope you feel better soon. Seems to be a common occurrence here in the Bay Area...

Erin