Tricky isn't it. I think that to save themselves going mad, the schools need to have a basic trust that all the parents are trustworthy enough, unless proven otherwise, and then look at how the risks weigh up against the benfits
At sports day the risk of letting people take photos is presumably that soem creepy parent takes photos of children in their sports tops and shorts, and posts them on the internet - or shares them with local creeps...
The benefit is that parents get keepsakes of some of their children's proudest moments.
Damn, now I'm confused. I thought it was an obvious answer in favour of letting people take photos, but the risk s so unpleasant, even though it's 1 in 10,000 sports days or whatever.
Maybe schools should get proper photographers to do the photography, and let parents buy photos of their kids.