[unwind]

This is not true at all.

First, of course, there is no requirement for NULL to map to address zero.

Second even if you do en uo there, many architectures don't even have memory at 0x0. Spurious writes are spurious writes regardless of whether or not you get a fault. You are still not doing what you want to be doing.

[ratmice]

even worse, there might be something there like the exception vector table, in which case spurious writes become an attack vector.

https://cansecwest.com/slides07/Vector-Rewrite-Attack.pdf

[throwaway84742]

Ones I worked with did nothing on when reading from 0x0. I mentioned this because for someone who spends all their time well above bare metal this is not intuitive at all. And null is de-facto 0 on all C compilers, even though it’s not required to be. So let’s not engage in hyperbole here.