In some of the work I do I come across people who have been prosecuted for the activities you describe. They are few and far between simply because detection is not easy. However, one miscreant made it quite easy when he closed in to within five feet of an unmarked police car travelling at 70mph in the overtaking lane of a two lane dual carriageway. He stayed there with his headlights and spotlights on full beam for about half a mile before cutting to the nearside lane as soon as a gap appeared and �undertook� the police car.
He was prosecuted for dangerous driving (it had gone beyond �careless�), was ordered to do 100 hours of unpaid work, disqualified for 18 months and had to take an extended driving test after his ban.
Driving with foglights on in clear conditions is not often prosecuted in my experience. Usually if offenders are apprehended they are simply warned of the law (many people don�t know it is an offence) and sent on their way.