[Electra Glide in Blue]

Plus the local ne'er-do-wells like to tie washers, bits of metal to the brushes overnight. So unless throughly checked each morning you might end up with a clean car right down to bare metal. Then there are wipers and aerials ripped off by the brushes. At least the sharks fin aerial is robust.
I used to work in insurance and saw the results both from insuring motorists and garages.