I’ve noticed in car forums that people tend to block out their license plate number when they post pictures. Why? It’s a fairly public ID tag that’s shown to the public everyday isn’t it? What type of information are they attempting to protect?
If they’re on a forum on which flame wars are common, they may want to preclude the possibility of anyone carrying a dispute into real life by finding out where they live and slashing their tires. (I’ve been flamed badly and stupidly enough on some car forums to be tempted to do this myself. J/k!)
Another possible scenario: if they’re doing anything illegal, or outside what their insurance company would cover, they may be protecting themselves from another form of retaliation. For instance, insurance companies have long excluded racing incidents, but many would cover the kind of track activities in which I participate. Recently, however, many have ruled that they won’t cover anything that happens on any race track surface, whether it’s competition or not. (I’ve heard of people who were cancelled just because they called their insurance agent to ask if they’d be covered if they went to a driver’s ed event!)
So now many guys will cover their license plates with tape while on track, so that any pictures from the event that end up on the Web can’t be used against them by their insurance company.
Because their are people out there that can use the license plate number to find out the name and address of the owner. The odds of something nefarious happening when the license plate is seen on the road, zero. The odds of some whacko with too much time on his hands on the internet using the plate number to find out who the owner is, slim but there is the chance.
One reason I’d heard was to prevent “cloning” - where criminals get false plates made up that actually belong to a car of the same model and colour, in order to disguise a dodgy car (or simply so that any speeding tickets, London congestion charge fees etc go to some other poor unsuspecting schmuck).
Sure, the criminals could rely on luck to spot the right sort of car on the road and note down the number, but how much easier, if they’re looking to disguise (say) a blue Subaru, to go to a Subaru forum and browse for pictures of a suitable car.
That’s (one reason) why people blank out their number plates.