This has happened to me twice in my life...both times while I was working as a cameraman for a local news station.
The first did involve bikers. I was sent to cover a biker rally, by myself. I was annoyed by the assignment, having covered a few bike rallies before, I have often found it hard to deal with them between the massive crowds, and the constant...CONSTANT leering and getting hit on by the bikers themselves. Really, it would usually get so bad that I'd have to park my tripod and camera smack dab next to a patrol car. And anytime you're shooting a crowd, it is hard to get candid shots because every idgit and their mother feels the need to WAVE at the camera when they see it pointing in their direction. So I am quickly gathering video at the rally (which was a toy drive for toys for tots) , and I had set my camera on the ground to get a low angle shot of the bikes and I'm kneeling next to it. I see this very large, heavily tatt'd and pierced biker heading my way. I'm already formulating my icy rebuff to what I am sure is going to be either him hitting on me or trying to get on tv. He gets right up behind me and says "'Scuse me ma'am..." I reluctantly turn around to give him the brush off and he says to me "Could you tell me where I'm s'posed to put my Teddy Bear?" He whips out a large stuffed animal he had under his arm for the toy drive. Poor huy just couldn't find the drop box in the crowd. I helped him out.
The second time was actually 9/11, also while working for the news station. I was operating our live truck, feeding video and such being brought back from the scene...yes I was in NY. Our station was based on Long Island. It was about 5pm...and I was glued to the screens in the truck watching video from all the major stations in the city (NBC, CBS, FOX etc). Mostly I was looking to see if any of my friends working for those stations had been wounded or killed. Our live truck is always an attractive nuisance for looky-loos who always have to come up to our truck, knocking on the windows and annoying us while we are working. I've had people just walk up and open the door in the middle of us working on editing or shooting, and try to climb in the truck! So Here I am sitting in the truck watching the most horrifying thing I've ever witnessed, and I see this young guy heading my way. I had the truck doors open that evening because it was such a beautiful warm day. The guy was in his late teens and he looked like Syd Vicious...Spiked hair, chains, tats etc. He makes a bee-line for my truck and I reach for the door to slam it shut before he can get there, but I got tangled in some wires and couldn't reach it before he got to me. The guy pokes his head into the truck, and now I'm MAD. I know he's here to gawk and with the tragedy of that day I was not about to deal with him. As I'm about to unload both barrels of my "righteous fury" he looks at me, teary eyed and asks me "Excuse me, so you know where I can go to donate blood???"
I burst into tears, made a phone call to my assignment editor and found that guy the local place for him to go donate blood for the 9/11 victims.