Earlier quoted context omitted.
You are correct; sad that most people don't know this.
Why should they? The only time it would be relevant is if you forgot your ID, and if you want to rent a car or hotel at your destination that might be a problem there as well. Knowing the TSA, I bet this adds at least an hour to the trip as you are begrudgingly walked to some back room and sit there for 20 minutes while someone is pulling up your file.
ADDED: It appears that as of Oct 1 2020, this sort of exception will no longer be possible.