These are the tags for items like strollers/car seats, etc. They were placed so that handlers knew these items needed to be brought immediately to the jetway, not to wait send up immediately and do not sent to bag claim. They were given out even on mainline, unlike pink valet tags that only were used on regional flights.

Either GA was mistaken or they're using them as she states. However I'm willing to bet she's mistaken. If these were going to be used as she said I'd wager DL would made tag say Skypriority.

All these tags are scanned. It may not attach the number to a specific passenger in system, but they're scanned on/off the plane. Like all bag tag numbers, the number can be reused.