[theodric]

If you do that, you're losing grounding, which will result in the machine having that AC leakage buzz when you touch it. The chrome lug that the plug nub slides onto is a ground connection, and the Apple official cords and some country-specific nubs implement the ground brush connector. There is (was?) a third-party Schuko (not Europlug) nub.

[wolrah]

Those power supplies often shipped with both a full cord input which was grounded but also a folding two-prong component that made it in to a wall wart and of course was not grounded.