Plastic License Plate Sheilds / Covers ?

Wasn't trying to set anyone up, there is no purpose for doing so. I'm just trying to understand the purpose or need for such devices. Since I've been driving at 16 yrs old I knew it was a bad idea to use such a cover. In fact an old girlfriend used one many years ago before I decided to get into law enforcement and I tried to get an answer out of her on it...never could. I warned her that she could get stopped for it but she doesn't seem to care... I just don't get it.

I'm not sure if it's the plate designer's intent to make the plates more easily read with stamped letters/numbers but I know for a fact it allows them to be read even if the plate is completely covered in dirt or mud. I've read them myself under such conditions. Unstamped plates would be totally unreadable.

I look at hundreds of license plates every day. Most people look one once a year to put the renewal tag on their own.