Indeed; car + Plates means a vehicle check. Can get your ID and registered address. If you happen to post a picture or something liked to an account it would be pretty easy to track down all your information within a few hours.
It isn't that the risk doesn't exist in the real world, its just that you might see 1,000 people in a day and piss off 5 of them. On the internet your details remain "forever" and a few poorly chosen words may incur someone's wrath. Probably 1bn people who can speak English and use the internet, gives you a much wider net for picking up stalker-murderer types.
Re-reading that sounds mega paranoid but trust me, nerds are to be feared more than any redneck with a shotgun.
doing a plate look up is restricted to law enforcement and issuing agencies, and it is well regulated, every look-up is logged and must be signed in to do
a citizen (as in non LE) can't do it
in the UK a citizen can do a plate look-up and get name, address, etc.? that sounds dangerous
next to impossible here to reverse look-up a license plate