I always find that weird.

You don't need to supply your birthdate for a domestic flight.

You don't need ID to get through CATSA.

But you need ID to board. Unless you're under 18.

And while I think I'd be questioned now if I said I was 17, I probably could have pulled it off when I was 22.

And what are they going to do? Ask for proof of age? Somewhat defeats the whole purpose of this.