My guess would be that parents are constantly taking photos and getting in the way of kids playing, or their performance, and it's to encourage parents to just enjoy their kids. This sounds like a pretty good rule to me. I'd have to guess that during their childhood your children will have multiple orders of magnitude more photos taken of them. I'd only worry memories will be lost by an overwhelming amount of media being saved about them.
I think that a general law against posting pictures of kids on the internet could just work. It's not just perverts, kids cannot consent to having their images stored in photographic databases forever and being IDed off facial recognition.
My guess would be that parents are constantly taking photos and getting in the way of kids playing, or their performance, and it's to encourage parents to just enjoy their kids. This sounds like a pretty good rule to me. I'd have to guess that during their childhood your children will have multiple orders of magnitude more photos taken of them. I'd only worry memories will be lost by an overwhelming amount of media being saved about them.