Facebook gets unprecedented traffic. They don't want things to go down so they... release changes constantly, a few times a day! They use peer review and their immense audience to see how well their solutions work, then iterate. The other teams *support* engineering, rather than being gatekeepers.
I actually did this at a medium-sized site many years ago. Push change to live, capture logs for five minutes while people beat it, then undo the change. It worked well.