Good point. I generally look at prominent display of BBB membership as
akin to a warning label. But complaining does have the potential to do
some good--you might help save the next guy from getting stung if he
happens to check.
IMHO, the BBB is (as has been pointed out) a protection racket for the
more shady businesses and a means of avoiding stricter regulation by
providing the appearance of a self-policing regime.