You're right that you shouldn't bet on all cars opening underwater,
but weather/waterproofing is not really an issue. Switches, relays and
motors (even the locks usually use motors) usually work just fine
under water at 12 volts without any protection, probably for hours to
days (until something corrodes too much). The battery will probably
leak down before the circuitry fails (maybe not if the computer is
involved).

Every scenario is not the same. If the car lands askew, sometimes the door
is held shut by debris or the bottom. And sometimes, **** happens, and it's
YOUR car that won't function underwater.

I am/was a scuba diver, certified twice, instructor once, and completed hard
hat commercial diving school. I've spent more time in a decompression
chamber than most people have spent underwater.

The scenario of drowning in a car is overblown. If you have ever watched a
demonstration of actual escapes, you will see that you have quite a bit of
time to get out. And popping the window early on with a wall of water just
outside waiting to hit you in the face with all those tiny glass particles
isn't the best idea.

The proper procedure is to follow the air bubble up, and when you are about
to run out of air, pop the window.

DON'T FORGET TO EXHALE SLIGHTLY ON THE WAY TO THE SURFACE, or you'll die
from an air embolism rather than drowning.

Panic is the cause of most deaths in this scenario.

But yes, a spring loaded center punch is worth it's weight in gold in that
scenario.

Steve, NAUI CERTIFIED, NAUI INSTRUCTOR, OCEAN CORPORATION OF COMMERCIAL
DIVING GRADUATE WITH SIX YEARS COMMERCIAL DIVING EXPERIENCE