I agree that actually measuring the real emission is a good idea, but there is a way of checking that the binary and the source does not match, at least in the

I agree that actually measuring the real emission is a good idea, but there is a way of checking that the binary and the source does not match, at least in theory. The way is to require reproducible builds. If the source is built with a specific compiler with known source and known parameters, and the source of the system in question is available, then running the compiler will produce the exact same binary every time if the compiler is sane. If all of this is published, then it is possible to check that the binary in the cars firmware and the binary produced by the published source match bit by bit. This isn't just some sort of academic exercise, but something that have been demonstrated to work in practice. In fact debian try to make this work for the whole distribution. This may not be totally practical yet, but this kind of checking can be done if the vendors are required to make reproducible builds and the regulators bother to check. All of this are big ifs, but at least in theory it is possible.