Wouldn't it be much nicer to live in a first world with more clarity, where it is immediately obvious which nation either knowingly bombed a kids school, or what other nation knowingly uses some poor children as human shieds...
But thats not the world we live in: apparently we live in the world where the event also happened, but where the rules weren't set up to provide such clarity a priori. And this second world is IMHO darker than the also dark first world.
The problem with that idea isn't that a country like Iran would fail to properly declare all of its schools, it's that it would improperly declare military targets as being schools. No one could trust the maps.
If you really wanted to do something like that, the maps would have to be compiled by some neutral 3rd party with on-the-ground verification.