Doesn't your "Starbucks test" exploit the router, not the MacBook? What does that prove?
As long as it's able to get at the Macbook that's what counts. One could use that same/similar excuses for most Windows exploits. That never stopped the Applebots from attacking Windows at will anyways.
What does that prove?
That the macbook is not as secure as Steve Jobs and the Applbots claim? In fact, Win 7 has consistently proved to be more secure in tests than Snow Leopard.