Yep.. in a typical MITM scenario (say, at a coffeeshop or a hotel in a firesheep sort of attack), server side checks won't help you at all since the MITM recurs

Yep.. in a typical MITM scenario (say, at a coffeeshop or a hotel in a firesheep sort of attack), server side checks won't help you at all since the MITM recursive server could just keep spouting those lying lies :)