As we know Boarding Pass and Passport verification has been changing. For our trip to and from BCN we did online check-in. Only my Boarding Pass was available for Smart Phone download or print. Kiosk was available at SLC prior to security. Two years earlier we had no problem getting two boarding passes on two separate phones both at SLC or Rome. It is my belief Delta wished to scan our passports without customer service. This was confirmed when Delta agents, at the gate desk, stated they did not need to see our passports. Two years early an agent had to look at our passports. On return from BCN-AMS-SLC. Again, a similar experience. A glitch, my husband was a random SSSS. At the gate he was checked for explosives and experienced a pat down. He had his man purse for computer and had handed me his carry-on. I said it was a good thing he did not mention he had handed me his luggage or we would have been pulled off to search that bag. AMS security utilized kiosk passport scan, ugly picture and AMS stamp from a human. I asked "When will the powers to be do an electronic stamp?" A lol moment from all.
SSSS isn't a glitch, it's a security measure... ??
I'm surprised they let the handoff of the bag slip past them. They usually don't.
The physical stamp is there so when the electronic systems fail, they can still tell you have gone through the proper processes.
Why have a passport at all for air travel? Simply use a kiosk where you give your thumb print and they take a picture to compare to what is on file. If it matches, you get through. But I guess there are still parts of the world where technology is not dependable, so this would not be 100% possible. Also, some countries are very nosey about where you have been and want to se the stamps in the passport book!