Hi Have been reading this about pro's and cons of removeable towbar. Would have thought it depends on the type of vehicle you're using whether form or function comes into play. If you're driving a saloon/hatch fine you'll probably swing towards form(looks) if you're driving a 4 * 4 looking vehicle it'll probaly be function and will suit the looks. As for a rear end shunt, I don't know if you,ve had one lately in a modern car but I shouldn't worry about the bumper, don't forget the front and rear are both crumple zones. Up to 5-10mph the bumpers probably fine but after that, well you'll find out how cheap bumpers are. As for reversing sensors, how long is your towbar? I get plenty of warning before my towbar hits, and in car park situations the towbar will probably save having the nice shiny bumper flexed in and cracked, especially if someones drives into to you, which is more common on car parks.
So coming back to it if is more aesthetically pleasing without a bumper, whip it off if not why bother? Perhaps they'll soon make one that retracts under the boot at the push of a button soon, it'll look ace as it slides ready to tow.
Regards Tom