Here's an update based on my experience going through MAN T1 security "priority lane" twice in the last couple of weeks.

I was flying in Y and had hand luggage only on both occasions (i.e. did not go to the check-in counter for a fast track sticker) and my LH *G card was enough to get me through the first hurdle. Before the gates where BPs are scanned there was a sign directing those who have not paid for fast track access such as frequent flyers to use the gate on the right.



This seems to be because in order to use the gate on the left you need to scan a barcode on your fast track receipt as well as your BP. After going through the gate on the right I was directed to the second (fast track) lane. Since this happened twice whether there were other passengers immediately in front of me or not (on one occasion behind a family group of about a dozen people with at least two pushchairs but also when there was no one in front of me at the gate), it looks as if they have changed the procedure.