Irrelevant IMO.

(B) and (C) are things that one voluntarily agrees to do with some potential gain for themselves. You either travel for work, for fun, or even for mileage run. But you are gaining something for the travel. You eat airline meals because you're hungry, or are too lazy to bring your own food, or like the hot airline food better than the smashed sandwich you could pack or meal you could get from the food court.

(A) is something that airport security (particularly the UK and any place that is making the strip search mandatory or giving the impression that the strip search is mandatory, including some "rogue" TSA stations) is imposing on the passenger with no gain for the passenger undergoing the risk. I know 100% for certain that I am not a terrorist. And I know that someone has not secretly concealed a weapon/explosive/incendiary on my person. So I gain nothing by going through a backscatter. The only person who gains anything are the nervous nellies who want to see everyone else get x-rayed so that they "feel safe," and for that matter, want to see anything and everything done for the sake of making them "feel" safe.

Take medical x-rays for instance. In general, an x-ray will not be ordered unless there is a benefit to the patient that outweighs any risks. So I might have dental x-rays to see if I have cavities. Or an x-ray of my leg to see if it's broken. Or even a CT scan (quite large dose) to diagnose an organ plan. But nobody has x-rays for grins and giggles. And nobody has an x-ray ordered for the benefit of someone else, not the person receiving the x-ray.