I recently took CO28 EWR->LGW in Y and noted that everyone around me had bag tags on their carryons that had alternating blue and white stripes. I had no such stickers and wondered what they were, so I asked someone in an adjacent seat. They were, apparently, given at checkin in what seemed to be a way of counting the number of carryon bags each person had. I had checked in at the BF desk where I guess the limits are either different or not enforced. Either way, the "security" folks didn't seem to know or care about this and neither did the staff taking boarding passes.

Is this new? Are they enforcing some limits now that they were not before?