It may depend if the test cars are used on routes with lots of homeless people or not, for the Mountain View test center I know of a handful of regularly seen homeless people on loaded bikes nearby in downtown Los Altos/Mountain View but it's not close to the level of San Francisco/San Jose/Oakland/Los Angeles/Anaheim/San Diego.

To a computer that’s never encountered this scenario before it might be.

She had a bunch of shopping bags hanging off the front. I imagine that could change how it was identified.