> At only a minority of restaurants do tips get shared with the cooks.

I think they often do get shared with cooks, but not to the extent to anyhow influence the quality.

Is this a regional/local situation where you live? I've worked at a handful of restaurants in the Northeastern US in the back-of-the-house staff and never once did cooks get a cut of tips.

Not sure, I just heard it from "friends friends"; the region is Midwest.