Those covers are designed to mask the plate # in the event that one of those red-light cameras takes a picture of your daughter running a red light...your daughter was no-doubt aware of that, so I don't really have much sympathy for her and the $128 ticket.
I see many vehicles with those covers...wish the cops would ticket every single one of them.
BTW, why are you paying your daughter's ticket ??
If that's what those covers are for -- to try to get out of a red-light ticket -- then that's not right to put one on. I don't really think that would work anyway.
The only useful purpose I could see for the clear cover is to prevent registration tag theft. The best way to do that though is make sure you scrape off the previous year's tag before you put the new one on and don't just put one tag on top of the other on your license plate.