In my experience, and I hope others will weigh in, the typical questions we get while doing street reference at demonstrations are from reporters and bystanders, "What is the event?" "Who organized it?" We sometimes get more in-depth questions, like this one about the electoral college system. For a question the street librarian can't answer on the spot, she will call a home support librarian. I haven't done much street reference since smart phones came out, and I don't have one anyway, so I'd probably still call for help, but someone with an internet connected phone might be able to answer a research question without help. At first we hoped that we could wear Radical Reference hats that would make us as recognizable as street librarians as the bright green hats National Lawyers Guild legal observers make them. We found that it was more effective to wear tape or patches that say some variation of "Ask Me: Radical Reference."
Although street reference was the primary idea that sparked Radical Reference, as we've developed the service, it's probably the smallest component of our work. Questions and answers on our website, and also Reference Shelf resources are more prominent as far as time spent by Rad Ref librarians on a regular basis.
For those of us in areas with active collectives, local activities like work projects and peer education events are central to our involvement in Rad Ref.