Relying on Nat's "discount", while watching a failed version of the same tactic going on right in front of you, sounds hilariously dumb/naive.

Refuge in Audacity.
It ALWAYS works.
For certain definitions of "always", with qualifiers.

Not exactly the same tactic. High-level diplomacy or thievery is more likely to work than low-level thuggery.

Luke: "Who should we be helping?"
GM: "plot plot plot plot"
party: "Nah, let's just ignore it"

Well, to be honest, I don't really understand who the GM is expecting them to help either.
Or what to do at all.
Maybe they're supposed to help the chef to impress the head-chef, but other than that?

Personally, if I was the GM doing this I'd be doing so as a way of explaining why it is that our good ol' Waiter #3 is so awesome, he's in the company of retired adventurers and a one-legged legend! Nobody is supposed to help anyone else, at least, not yet.

I'd say the GM was just letting them some choice about where to bring the plot now. since his plan to have fullbody as the boss is failed, he decided that he might as well let them do.
He might railroad into going where he want them to go, but once they're here, it's up to them.