The double sliding doors are to minimize the impact that the outside temperature has on the inside. These have been around for years and I've never seen one in place that can block someone's egress.
You are correct that many subway systems have something in place to verify that you were a fair-paying customer. It just doesn't strike me as equivalent.
In the subway case, it is there to prevent bad actors from cheating the system. It's lame the same way that people checking your receipts at Sam's Club is lame. In the airport case, you're assumed to be a criminal even before you've received any benefit.
You are correct that many subway systems have something in place to verify that you were a fair-paying customer. It just doesn't strike me as equivalent.
In the subway case, it is there to prevent bad actors from cheating the system. It's lame the same way that people checking your receipts at Sam's Club is lame. In the airport case, you're assumed to be a criminal even before you've received any benefit.