The exceptions to the rule are very rare. I can think of one case where a person shot back during a no-knock raid on the wrong address and had charges dropped because police didn't announce their presence well enough.

As long as they shout "police", they can knock down your front door, throw a flash-bang into your infant's crib and disable them for life, then go "whoops" when they realize they have the wrong address and you'll be on the hook for replacing the door they destroyed.