I have not heard Bitcoiners routinely advise each other "If you buy something with Bitcoins, you probably should not attempt to buy something else for an hour."

I have not heard Bitcoiners routinely advise each other "If you buy something with Bitcoins, you probably should not attempt to buy something else for an hour." That's a necessary component of any defense against these shenanigans, at least until the One True Bitcoin Client starts to differentiate between change which is 6+ confirmed and change which isn't yet.