[Geezer]

Leave them on. They protect the paint from abrasion from road debris.

 

[Geezer]

Hmmmm, so all of you kept those plastic things on even it might collect dirt and created a black outline? That is my concern.

If you're driving a Super White xB, the black outline will eventually show, but you should be able to clean it up with a little extra effort. With any other color it's a non-issue.