Never. However, I've encountered someone using the bathroom to clean up, and informed her where showers were available in North Pole. She was  unaware of them and thanked me.

And to reiterate, if the homeless are going thru the doors at your public library, it IS THEIR BUSINESS. It's their facility, and they have to deal with this directly, instead of waiting on 'someone to help them.' 

At least they're being proactive as they can be with the tools they have at hand. I guess you missed this sentence in the article:
***Now the city is trying a cutting-edge approach to the issue: For the first time, they will station a social worker inside the library to help some of the Anchorage's most vulnerable in a place they're already frequenting.***