This isn't about Rust, the same problems were well known (and long suffered & complaned about) before Rust came around and there are well known much older engineering techniques for parsing untrusted data. It's nice that the Rust phenomenon has brought with it some new spirit of vigor and momentum to break out of the apathy, though.

Re Rover code and ECUs - this is the difference between safety critical code and security critical code at the attack surface.

The first kind deals primarily with "don't keel over or go crazy when natural phenomena throws unexpected circumstances at you", the second deals with inputs crafted by intelligent adversaries who can see your code and test & iterate attacks to exploit any flaws they uncovered through analysis or experimentation against your implementation. (Of course if we nitpick, an intelligent attacker is a natural phenomenon.)