You sound like a programmer who is completely ignorant of how legal systems work.
He sounds like a programmer who has seen how the legal system works.
Laws aren't written like "if photo.is_manipulated() then display_disclaimer() end".
Nope, you have that 100% true - Because that would give a nice, easy, objective test of guilt.
Instead, the law will describe 200 different varieties of manipulation, which the advertising
industry will neatly get around ("Well, it didn't explicitly ban radioactive waste to give the
subject a healthy glow"), while semi-pro photographers fear for their freedom if they
dare to sell a decent shot to a local paper. It will include zero funding for enforcement but
allow police to charge high-end cameras with a crime and thereby keep them. It will accidentally
outlaw Gimp (but of course they'd never enforce that, wink-wink-nudge-nudge) but not
Photoshop because of some obscure detail in their JPEG compression
implementations. And finally, just for good measure, it will provide 50 billion dollars to
build stronger levees in Nevada (or the French equivalent, I suppose).
And I wish I meant this as hyperbole...