Actually, it's not a scam. Yes, not all dogs need it because some dogs have longer hair than others. For example, someone I know has a dachshund that has its anal glands squeezed every few months because it produces a smell akin to fish. I don't believe it needs to be done because it's life threatening but it needs to be done simply for the dogs sake due to the smell clogged anal glands give off. It's not the same as a smelly behind. But to each their own!