I've seen single line changes cause data loss, corruption, system outages, remote root exploits...

I'm not sure that the number of lines makes the change more or less risky.

And how exactly does this relate to the way they deploy their code? As far as I can tell, they actually review code before marking it ready for deploy. That kind of changes would be an issue with "usual" large batch deploys as well.

I've also seen many devs look at a broken release and instantly realize their mistake. A forgotten production config, a hard coded variable, or an empty cache. If code is in fact reviewed before going to production, the risk is significantly lower.

Nice choice of username, by the way.

The safest change to make to a stable system is the smallest change possible.

Agree, it seems to me that an emphasis is on time production deployment takes rather than rollback vs fix