While obviously modern power tools sold in the U.S are plastic cased like the rest of the world, do they have the 'square within a square' symbol on them to indicate this, or is it only in the 220-240V countries?
Yes, the 'square within a square' symbol is used on North American double-insulated tools.
Electech:
Yes, it's always worth remembering that even a
cordless drill can electrocute you if you drill into a live conductor. Always be aware of possible paths to ground, and stay out of them. Good point!