

Yeah, don’t say you don’t know if you do, that’s lying, which is a crime in this situation. You can answer crime related questions with questions (avoidance). But don’t do that for everything. If they push, start asking if you’re free to go. If they say no, invoke the 5th.
Don’t do their jobs for them.
Don’t answer any questions that could incriminate you. Or talk to them in general. But be polite when you do speak.
Only tell them your name or provide other required identity information. Don’t say where you are going or coming from. Don’t explain anything. Don’t tell stories. Don’t lie.
Community bikes are not a new thing. They had them in my hometown through most of my youth and teen years, and may still. I don’t live there anymore. 🙁
They had a strong bike community, and a bike store and repair shop off a main ped/cycle path through town, just outside downtown. It had a lounge and was the primary source of the community bikes and their maintenance.
Paint the bikes all a similar bright color, not white, and get stickers made with info about use and contact info for pickup and repair.
Like, “I’m a community bike, use me as you like, leave me somewhere responsibly when you’re done with me, so somebody else can use me too. Contact for pickup or repairs 555 RIDE 4ME”