Refuse to serve, yeah for sure. But to take something out of your hand and tell you all of sudden it's not for sale? That's BS!
That would be the same as me taking a component to a clients house, installing it, liking it too much and saying "Sorry, you can' have this" all of a sudden. And then not give a reason. That's wrong.
Problems worthy of attack, prove their worth, by hitting back. -Piet Hein.