So you're unwilling to give up that No-Prize.
I think that this is an accepted notion. But you don't need it explained in comic books or movies. People should be able to figure it out for themselves. In fact, that's better. It's always better when the audience fills in the details for themselves, instead of the storytellers getting bogged down with trivial details.
As for facial recognition, I don't think that's a fool-proof technology. And it wouldn't be a problem for Superman to fool the system. I used to always mistake Susan Sarandon for Lesley Ann Warren but that never threatened either woman's career--if they really are two different people.