pat on the top of the head?

hey all,

i took my sv out today to some twisties near my house. right as i was approaching the area where things really start to get interesting, i noticed quite a few riders patting the tops of their heads as they passed me. i am a new rider and this was only my second time out there so i pulled over, thought of what that could mean, looked over my bike, made sure my head lights were still working (i recently fixed them), etc.

everything looked okay with my bike and i was riding reasonably, but since people were trying to tell me something, i'm a new rider, and i didn't understand them, i turned back for the day.

looking around, the only thing i can find online is that this might have meant there was a police officer nearby. could it have meant anything else? i can't imagine what i could be overlooking about my riding, gear, or bike that other people might have been trying to warn me about, but i'd really like to be sure.

thanks.
andrew davidoff