Especially when they're going to show up with a bus full of new grad MBAs and bill like crazy for each of them. A few whale charts and a huge billable later, they'll tell MM what she wants to hear and they're off to their next engagement.
I recall there being quite a few Yahoo employees and execs with McKinsey backgrounds. I think many of them were on previous projects that Yahoo hired them for.
If this is the case, I hope they get better results this time.