This is tangentially related, but I had my plane at the Tampa Bay AirFest this weekend, which is free to the public. I tried to use the situation as a training opportunity, so when a kid grabbed the prop, I would (trying to be relaxed) explain that you should never move the prop on an airplane unless you want it to start, as it is possible that it could. Mostly the message was met well, but one woman got a little upset and asked incredulously "is there fuel in it?". I said of course there is. She responded "Isn't that unsafe" and I responded "not if you don't mess with it", to which, kinda to my surprise, she replied "Good point" and walked away.
And now I have to share my favorite picture from the weekend, a group of cadets taking each others picture with my Chinese airplane.
And to bring the post back to the thread topic, my point is that maybe stopping and talking to the walkers about how hard it is to see them, what the possible dangers are, and giving them options would help? They might surprise you like the lady in my story did me.