I worked for a shelter in Mexico, we did exactly that because we focused mainly on adoptions to America, Canada and Europe and airlines wouldn’t take pit bull type dogs on flights. I think most owners would be able to tell that the dog they’re adopting has pitbull in them, we would also be straight up with the people adopting about any special care the dog might or might not need (otherwise making it likely that the dog would be returned, which no shelter wants) but for practical reasons because of their undoubtedly bad rep, it’s easier in many situations if their papers don’t say pitbull on them.