[Dalewyn]

There is a psychological element to it.

If there's a safety mechanism that may or may not work, coming to rely on it is suicidal.

If there is no safety mechanism in the first place, you (hopefully!) never become complacent in the first place.

So it's better to either have a safety mechanism that will absolutely work every single time or nothing at all, than one that may or may not work and invite complacency.