So my wife was working on a presentation, and needed a handful of pages laminated. Instead of using the local Kinkos, she decided to do it herself with some clear contact paper. Specifically "Clear Magic Cover" by Kittrich Corp. ($6.95 or an eight foot roll)
I looked at this stuff, it's translucent and vaguely reminded me of my LaserShield cover. So I decided what it'd do over a license plate. My tests were amazingly unscientific, but I'll share anyways.
I applied a strip of the stuff over the alphanumerics of a LP (the very top and bottom of the plate where uncovered). Then set up laser pointer so when I turned it on, it reflected off a part of the plate without the contact paper, and onto a wall.
(you can see the laser pointer at the top of the LP)
With the lights turned off, you can see the reflected beam from the laser pointer.
Then I repositioned the pointer so that it reflected off the plate where the contact paper strip was applied, and onto the same spot onto the wall:
(again, you can see the laser pointer on the plate)
And a picture of the wall with the lights turned out
That last image is rather pointless. My phone camera isn't sensitive enough to pick up on they very faint red spot that was reflected.
The laster pointer was approximately 2 feet from the LP, and the LP was about 5 feet from the wall.
The reflected laser point, reflected off a mirror (placed directly in front of the LP) was approximately .25 inch in diameter.
The reflected laser point, reflected off the LP without contact paper a diameter of about .75 inch.
The reflected laser point, reflected off the LP with contact paper was somewhere in the neighborhood of 25 inches in diameter.