Tell you what. Next time you're on a flight into or out of Washington National. . .
They tell you that you can't leave your seat for any reason for the first half hour after departing, or for the last half hour inbound.
Of course that's just a suggestion, not in the least mandatory or required.
I would hope that reality and other like-minded people use that opportunity to test the system. As soon as the pilot tells you the aircraft is "locked down," unfasten your seatbelt, get up and start to walk up the aisle.
Then report back to us about what is and is not mandatory. If you can still type.