Seattle resident here and ex-Amazon employee. Amazon has security staff (previously Securitas aka: Pinkertons) at all building badge entry points who specifically monitor for that kind of thing.
Also, it’s hard for me to believe that Amazon was ever NOT monitoring, measuring and aggregating employee badge swipe data. That’s far too useful a data point on individual employee behavior to leave it on the table. And there’s zero obligation to either the public or Amazon’s employees to disclose that they’re doing it.