writes:

And you know this how?

Because I actually do know how GPS works. And I know from questioning pilots
and from reading accident reports that most pilots don't know how it works
(like most other people).

And even if true, this is a problem how; by the non-existant huge numbers
of pilots getting lost or violating airspace other than TFR violations,
which is a separate issue?

Pilots rely on GPS for a lot more than just TFRs (actually, TFRs require more
than just GPS). They tend to rely upon GPS completely, even to the point of
never looking out the window. They don't realize their mistake until they hit
a mountain.

This points out another vulnerability: incorrect map data combined with a GPS,
which is even less reliable than GPS itself.

Another point you seem to have missed is that GPS displays a map and in
VFR flight you compare what you see on the map to what you see through
the window.

GPS has no notion of maps. The GPS unit may display a map, but the map comes
from a database that is independent of the GPS receiver and may or may not be
accurate. It's important to allow for that, too.