The problem is, you cant hide your license plate while driving.
So I believe doing it online is pointless
But then again
I am not on Social media, and that is where the largest amount of data is gathered for identity theft.
Very true Elff...but in the world of OPSEC the license plate number is just one piece of the puzzle.
Take Monopoly, the game. As we all may be fully aware of, in the game you must own all the properties of one color before you can build houses and hotels on them (and really break your competitors). So to build on the green properties, you need all three.
But if one other player owns one of the green properties and you own the other two, you're hosed unless you can get them to give up that other piece.
Now, if someone is stalking you and after you, they can read your plate on the street...sure. There is one green property piece. Now, they can follow you to work or to home and have another property piece.
But lets say they want to rob your house and want to do it when you're not home. So they go online with the information they have and start doing research. Since you drive a Sky, a very uncommon car, they figure you might be a car enthusiast so they start scouring the web for sites about the Sky and come across here. Let's assume your Sky is still stock and thus, other than color, your Sky looks like the hundreds or thousands that are already out there. You haven't put where you're from in your profile so they just can't assume anyone from your area on here is actually you.
They come across a post on Skyroadster, however, and see your license plate on your car in a post you made about it. Now they've identified your profile on here. So they do a search for all posts by you and find you're going on a ride next Saturday and plan on being gone all day. You're meeting the group at 8 am and having lunch at 2 pm. The starting and ending locations can be Googled (after all, they already know where you live) and they determine that it will take you 30 minutes to reach the start location and another 45 to come home after lunch.
So from 7:30 am until about 3:45 pm the have a window where they can plan on you being gone. Now they recon your house, figure out a way to hit it during that window of opportunity and have a cover story for your neighbors as why they are there "Oh, Bob had a water heater leak this week and called us in to replace the water heater and repair the water damage we find. We go back a long way. I work with him at XXXXX and he knows I do this kind of work on the side. He's off to one of his Sky drives today so he wanted us to have it done for him so he can take a shower when he gets back."
And this completely ignores the fact that once they have a picture they know you've posted personally, they can go on Google, search where else that picture has been posted, and find any other forum you've posted in. Then there is Facebook too...armed with that information they can look through groups and events for pictures you may post there, and with that may now have a name to go with your face...and kids names, wife's name, where you go to church, etc. Perhaps you just posted about that beautiful painting you just inherited from your uncle and have hanging over your fireplace. The more information they have, the better prepared they can be and the more vulnerable you are.
Replace the motivation, time, resources with whatever you want but the situation is the same...you've given them a few more pieces of the puzzle that they may not have otherwise had. Like I said, it's up to you how much you put out there and how much risk you feel you're taking but the question was posed as to why do it, and there is a very valid reason why.
For me, and people like Skersfan, Marvic, and MM, there is no point in covering up the plate. The cars themselves are modified in a way that makes them unique and someone who was after us could easily figure out it was us by just seeing a picture of the car. But other than my car, I don't own anything worth going through that much effort. However, there are other aspects of my life I do not share on here purely out of OPSEC protocols and for good reason. Just doesn't happen to be my license plate.