“No-knocks should be banned except for hostage-type situations.”
As I recall, they were introduced to deny residents the time needed to flush drugs down the toilet. If you can surround a residence, there’s no need for a no-knock just to arrest somebody.
If you have a hostage situation, you don’t need a warrant, do you?
I don’t know abut needing a warrant in hostage situations, although TV says no - but we know how accurate they can be at times.