I've (unfortunately) written plenty of "safety critical" code professionally and coding standards definitely have a negative effect overall. The thing keeping planes from falling out of the sky is careful design, which in practice means fail-safes, watchdogs, redundancy, and most-importantly, requirements that aren't overly ambitious.

While maybe 10% of rules are sensible, these sensible rules also tend to be blindingly obvious, or at least table stakes on embedded systems (e.g. don't try to allocate on a system which probably doesn't have a full libc in the first place).