"If we're going to roll this out let's limit it to reduce the numbers of people affected." Ime this is something senior developers would themselves do - and not only for changes they deem "high risk", but also by default.

I say this because this case a data file was changed. Probably done thousands of times without an issue.

QA would have never said "we need a staged rollout for this". Developers and those who set the process should do it.