Well, it doesn't show how broke you are.
And it's not "hide how much is in your car" it's "Volunteering information about a prized possesion." Why the hell would you put $70,000 into a car unless you want people to know it means a lot to you?
People who do this are basically telling everyone to look at their car, including thieves or someone wanting to take revenge on you. We've all bought something off of someone or eventually will. Someone out there has your address, or even just your name/city, and that's all you need.
I'm just too paranoid, but ahem, with as much as I've put into my car I wouldn't risk it
People are going to have to search through the threads and my posts to see what I have and they'll have their work cut out for them.