[Richard Crowley]

"Mr.T" wrote ...
"Richard Crowley"wrote ...
Several laptop power supplies (notably several Dell models)
use full 3-wire grounded power cords and apparently extend
the green-wire safety ground through to the computer power.

Maybe so, but it isn't all that common a practice IME.

An informal survey of the stuff at home and in the office shows
more than half use 3-wire "brick" power supplies. Maybe it has
something to do with safety requirements in various countries.