Originally Posted by Black Beauty
Maybe they knopw what your chossen profession is & choose not to be sociable to you

That could be just it BB - ahh a policeman's lot is not a happy one (well it is actually sometimes)
I think its just that
(a) Alfa's mean the same to them as any Ford would.
(b) They are very reserved or shy about waving - they might be afraid
of looking foolish.
(c) They could just be in a bad mood or may not have noticed your Alfa