[Doxin]

> The UK has had shutters on the phase that is opened by the earth pin forever. Which is why their plugs are caltrops

No, bad design is why they are caltrops. Over here in the Netherlands shutters are similarly required but none of our plugs need a third pin. The shutter is a see-saw construction that works in such a way that you need to insert both prongs at the same time for the shutter to rotate out of the way.

That said our grounded plugs are still caltrops for no real good reason, though less so than the UK ones. They tend to fall with the prongs to the side instead of prongs-up.