I have to say that when I give a pilots briefing before an event, I do not specifically caution the pilots to not make extended run-ins aimed at the crowd. Have never seen anyone do that at any of my events.
If some one did it for a few seconds with a light weight slow stick taking some pictures, it would not be an issue for me as long as the aircraft never passed over the safey line between the runway and the pit area.
if a larger faster model did the same thing, I would very politely ask the pilot to not do that. I would not argue with him while he was flying. After he lands I would look him up again and make my case as to why what he was going was a bad idea and ask him to not do that again in the friendliest way possible.
At my last electric fly in, a flyer asked if he could fly down the flight line with a fairly hefty quad with a video camera, in between the runway and the safety fence. I politely declined and he agreed to make his camera pass down the centerline of the runway, flying the quad with the "nose" pointed at the pit area, but moving slowly right to left down the runway, sideways.
The quad malfunctioned and dove forward into the ground just short of the safety fence. If it has been where he wanted to make the pass, it would have hit airplanes and possibly people in the pit area. Glad we dodged that bullet.