Not sure how long those have been around, but I think I got one at my first TK upgrade in 2015.

You get the usual red one when flying Y as *G at J check-in.

I haven’t seen them take luggage off people in the gate area on any of my flights, but if they do, I’m sure they are more lenient with J passengers.

It’s a nice touch but probably doesn’t serve much purpose beyond bragging rights.