Ball mounts Is it legal to have one when not towing?

I live in ILL and I have yet to see any "red" covers covering hitches and almost every truck I see has the hitch in.....I don't keep mine in but The only trailer I have is my TT with WD hitch but I do carry a hitch n ball just in case. I figure it would be my luck my regular hitch in it would rust in and then I wouldn't be able to pull my TT. I also have never heard of anyone being pulled over and issued a ticket for having a hitch.....