Yes, I think it's a matter of In for knut, in for a galleon, isn't it?

I think we're better off swearing them in, so they can give us a bit of warning next time before they pop into Laszlo's kitchen out of the blue!

And so they could call us if they ever really need our help. I know they can ask Hermione or the twins to write us--or Terry--but that puts added time and chance between us. What if Hermione and the others simply don't look in their books at the moment they're needed? It can happen to any of us, but if they've got to have a go-between, that increases the odds there'll be a delay.