Even if your carrier actually enforces such a policy, the actual implementation is trusted to that part-timer on minimum wage you showed the ID to. They push "OK" on the ID check step, and it's done.

What do you suppose happens when the hot guy in the club who bought them and all their friends a round of drinks says they can make a month's salary in ten minutes if they allow a few of his mates to skip that "annoying" ID check?

And I'm sure that afterwards, once the carrier figures out who was responsible, they'll get fired. But meanwhile your accounts were taken over and leveraged for some scam or (if you own "cool" things like a short Twitter handle or that rare drop in a video game) sold to the highest bidder.