A colleague was pulled over by the police and sternly told off for using unnecessary fog lights. Mind you, this was in twilight on a totally non-foggy day. It turned out that when he bought it, his car had come with its foglights set to permanently on, and he'd driven it like that for 3 years without realising. So, yeah, really this story doesn't so much prove that They do indeed tell you off for having unnecessary foglights, but that you can do it every day for 3 years without Them complaining at all.