Is there anything that we can do to correct this misconception. I know the breeder that we brought Jasmine off does not take the white pups out of the bag when they are born.
First, don't buy from breeders like this....(sorry, but that's how I feel - kind of like the pet store thing). (BTW, does she stop the dam from removing the sac? If the dam does not try to do it herself, there's a whole other problem....)
Second, get your white Boxers out there in the public eye. Get CGC's on them. Train and compete with them in Agility and Obedience (this year's High In Trial for Agility at the National was a white Boxer name, appropriately, Justice

) - it sends a message. Join your local Boxer Club and work from within to change the system. (Just a note, though - if you have bred or registered a white Boxer, you will not be able to join a club, as it is against the Code of Ethics. ILP numbers are OK.)
I don't advocate becoming a white Boxer lobbyist

, because I think subtlety will work much better in this situation than in-your-face-ness. But if you are out there with your whites competing and doing well and proving that they *are* Boxers, regardless of their marking pattern, people will slowly get used to the idea....but again, it will take time.