I've got 3 cameras hard wired not for running into muppets as the'd be pretty dumb to let me hit them, their so I can see bits of the truck / trailer.
one on the pickup hitch and arms which means you can put the towball straight on the hitch, the other on the cab roof facing backwards and the third is a wireless on a spotlight which is magnetic, it means that I can reverse in the dark up the drive and see where the trailer is when it's raining on the mirrors.
I wouldn't be without them and don't hesitate in getting them fixed when broken.
Ed