Imagine a car being covered in such material, I'd rather not be in it on a busy road. ;)
Yeah, that'd be terrible if nobody else could see you.You'd get cars pulling out of junctions in front of you, and not using their indicators, and tailgating you, and dawdling along at 30mph in a 60mph limit so you can't get past... actually I'm starting to think my car has a cloaking device installed already... :/