One year at Americade (Lake George, NY) a group of stopped to spend a couple of hours in the vendor area. After putting locks on, jackets off, etc we walked to the vendor area. Two hours later we went back to the bikes. Sitting on the seat of my bike was a digital camera with a note on it. "I found this on the ground and remember that you had one in your helmet (which had been on the ground while I was locking the bike). I hope this is yours!"
That camera was about a month old and was over $400. The person didn't even leave their name, so I had no idea who to look for to thank. I only vaguely remember what kind of bike I had parked next to, which was now gone.
There are still a few good people out there.