[Alberta's Child]

It's real, and it's actually pretty simple. It's made of a series of louvre-like plastic tabs that allow your license plate to be seen from directly behind the vehicle, but makes it impossible for the plate to be read from a point above the vehicle and off to one side (where red-light cameras are typically placed).

[okie01]

"It's made of a series of louvre-like plastic tabs that allow your license plate to be seen from directly behind the vehicle, but makes it impossible for the plate to be read from a point above the vehicle and off to one side (where red-light cameras are typically placed)."

The "Venetian Blind Effect". Simple. But effective.