I'm sure this has been asked and answered so feel free to point me to another thread, but I'm just curious exactly what the boarding pass scanners at TSA actually validate. Do they actually pull up all the flight/passenger details? Is it connected to airline systems? If a flight were to be changed or canceled, would it reject the boarding pass? Just curious about the details since I was just remembering the old days of meaningless scribbling they used to do with your BPs.

Cheers.