Guys, as someone living in Bavaria, I am truely SHOCKED to read such crap, sorry to say that. Those who have done well with summer tires in snow either don't have a clue what a difference a winter tire makes and/or they just have been lucky to catch up some fresh snow which isn't as slippery as many think.
No offense meant but there is a reason why you loose your insurance in Germany when you have an accident on summer tires during winter time.
Braking distance alone is substantially shorter with winter tires, not even talking about sidegrip and traction.

Maybe this example helps:
when braking on snow from a speed of 50 kph (31 mph), the stopping distance with summer tires is aprox. 45 meters. With winter tires, it is 25 meters, almost half. This alone should raise some eyebrows.