Insulating layer?

The linked Itanium example doesn't dereference uninitialized pointers anywhere - it demonstrates that just attempting to store an uninitialized register value might fault. In essence, this could blow up:

int global;
void f() {
int uninitialized;
global = uninitialized;
}

Ie. direct example of an architecture where what you wrote ("But padding, uninitialised variables, etc etc are perfectly valid to dereference. You can reason about it, you're going to get random garbage back.") doesn't apply.