Happened all the time during the month I rode with a modulator. People would just freak out and pull over infront of me. Took it off because it just made the car ahead of me unpredictable and dangerous.
Once when DM and I were taking a break in some Adirondack parking lot a group of Europeans in a SUV pull up next to us. Some attractive woman get out and starts telling us about some hiking trails they are trying to find. I tell her it sounds like a great place. She looks confused, then asks...aren't you police officers? Sorry, no. They drive off no better informed.