What does having GPS have to do with how the terms "dead reckoning",
"deduced reckoning", and "ded reckoning" are applied.

most mariners who can use a gps have one or two or three onboard, and thus are
likely to hit the rocks by wandering blindly in a fog thinking their "dead
reckoning" navigation has them dead bang on course with dead on precision that
is dead on center and dead even with expectations.