It's technically possible, but in practice that's never how it works. The entire purpose behind no-knock is to take them by surprise before they can even think about resisting. They use immediately overwhelming "non-lethal" force so that they never have to escalate to a "lethal" level. Obviously the definitions of these terms are imprecise at best.
Believe it or not, this is the safest way to do "no-knock" for everyone involved. Think about it- if a law-abiding gun owner was woken up to the sound of unknown men breaking down his door and had time to access her weapon, the situation would be much worse for everyone. There have been many instances of this exact thing happening, often resulting in the death of the raid victims and/or police officers. That is why stun grenades are always the first thing that goes into the building during a no-knock raid.
Unfortunately there are several stories floating around where the law abiding gun owner was at the far end of the house and had enough time to get a gun out and fire through the door at the calamity coming forth. Which has frequently lead to the death and/or life time conviction of said law abiding gun owner. This might be ok if it weren't for the frequency with which these law abiding gun owners had their homes mistakenly raided.
So, a bunch of armed men breaching a door and rushing into a house is less likely to provoke such a response? No knock entry is dangerous, period. It should only be used where threat of violent opposition is well established. Once you're going in no-knock, the notion that flashbangs is the safest way sounds plausible.
What if, you know, they did knock, then the law-abiding gun owner would come and open the door, like in most of the civilized world. Or take them when they are out, wait for them to get home, etc. There are numerous ways to make an arrest without going all commando.
Parent said this is the safest way to do no-knock. Everyone in this thread agrees that no-knock is a bad idea most of the time (at least), and clearly in this case. Up thread, there was question of the particular tactics in conducting the no-knock entry.
I said safest, not safe. I'm not trying to defend no-knock raids; I believe them to be immoral, dangerous, and unconstitutional. I was merely trying to explain why these tactics are used.
Yes, it is true that the most efficient way to oppress people is to do it with maximum available force and brutality, such that they are utterly unable to resist.
Wouldn't it be reasonable to observe the house for a while before a raid? That's where you pick up on clues as to who lives there. "Hmmm, seems to be a lot of small children here and not too many gang style criminals. Ok, team, we go in fast, but force probably won't be necessary." Oh, wait. This type of thinking would probably prevent the no-knock raid to begin with.
You could have no-knock raids to capture evidence without needing to stun everybody.