The cards themselves detect each other without me knowing it? Checking into to JimmyJohns with a loyalty card is not the same as the guy I passed on the street

The cards themselves detect each other without me knowing it? Checking into to JimmyJohns with a loyalty card is not the same as the guy I passed on the street's phone checking my phone and both letting JimmyJohns HQ that we passed each other at 12:53 on at 643 West Main St.