I am sorry that makes no sense. Many people don’t scan at security at the timing point - to be clear we aren’t talking about the initial entry point scan.

No one has ever described being called at the gate because of it. I didn’t scan on Monday and nobody cared - I boarded my flight as normal. Considering the numbers of people who don’t scan at the timing point there should be loads of similar reports over the years on this board, and quite simply there aren’t.

EDIT: the thread in question where you mention it https://www.flyertalk.com/forum/brit...ed-out-1f.html

I am sorry, but there clearly was something else in play here. This wasn't an issue because one person failed to scan at the timing point. Countless people do not scan and yours is the first post ever I recall which suggests a link to FLY and causing an issue on boarding. Either everyone else over the years has somehow been missed by this BA check (including myself many times) or I think you may be mistaken. I am sorry I am not trying to contradict you, but look at the evidence on both sides here.