I’ve been traveling around the world. It is 50 / 50 of the socket is properly grounded —-anywhere in the world. I get a tingling zap on the wrist when not properly grounded. The charger also gets hot and sparks.

but it's never going to be grounded, there isn't even a ground pin on the charger

Apple sells a 3-pin extension cable

US Version: https://www.apple.com/shop/product/mw2n3ll/a/power-adapter-e...

Yeah they sell the 3-pong extension for various countries. I am currently using the Indian version of it.

If you swap in the extension cable head, that does indeed have a ground pin, at least in Australia anyway. The grounding comes from that metal ring that the connector uses as a guide. https://www.apple.com/au/shop/product/mw2n3x/a/power-adapter...

only two prongs of which make it through. Usually the regulation as I understand is that it's fine if you can prove the case can never get in contact with anything electric, for most laptops that's just being made of plastic.

As has been established in other threads here, the metal button thing the prongs slide onto is an earth connection.

> only two prongs of which make it through

The big recess above the pins is what encases the button of the charger and provides grounding if it includes metal strips. Assuming the charger itself has a metal button.

In the EU a grounded cable has been the default forever (I have a grounded cable from my 2010 MBP which I use as travel cable for my 2021 MBP)

>The charger also gets hot and sparks.

Some heat is normal, but the sparking seems concerning.

That should not happen with a well designed power supply. It sounds like Apple cut some corners "for design reasons", or some shortcut to make it cheaper to manufacture.