I’m not sure that will be the reason. Using NFC for entry to the ground and then NFC for buying food and drink probably shouldn’t allow them to link the two things under data protection rules. That said, I am sure I read somewhere that this season they were going to ask for NFC checks of supporters’ season cards for the 10% discount (rather than just the server looking at the phone screen), so that may allow them to do so. Not sure it gives them much other than who is using their discount and who isn’t.