Just a little friendly advice for all...
It varies from state to state, but generally speaking, concealing a VIN could stir a confrontation with the aggressive and less privacy tolerant LEO. The LEO has a right to view the VIN without disturbing a motorist. He also has a right to disturb a motorist when he cannot see the VIN. In some cases, a concealed VIN is a felony. In some cases, it's probable cause for seizure of the car, and the LEO can tow the car for a confidential VIN verifications and then "hold for owner." You pay the tab. This VIN stuff is the LEOs turf, and rightfully so, in order for him to protect our property. So, do what you gotta do, but be careful.
The purpose behind posting the VIN on the dash, was to allow LEOs to identify vehicle status and ownership with as little intrusion as possible into the privacy of the owner. Hide that, and you may be detained longer than you need to be detained in any casual street stop, until the VIN is revealed and confirmed. You'll probably stir some other "probable cause" thoughts and find yourself standing on the side of the road while the LEO searches for the confidential VINs located elsewhere on the vehicle. Give him the probable cause to do that, and everything he sees in his search, is in his plain view. Now, I don't think this is an issue for most of us here, but, why put yourself through that to begin with? Please check your local laws, because also generally speaking, this rule of thumb applies to license plates too, with all those smoked and louvered "anti-radar" license plate covers that are so fun to buy, and so hard to explain.
Any lawyer can tell you, there are dozens of rights and protections afforded us as citizens travling a public highway. However, there are also dozens of responsibilities we must carry out to maintain our protection, and when we fail to do so, the LEO has his responsibilities he must carry out. It's a chain of probable cause events and a nightmare, why put a kink in the chain?