[iLoch]

No knock entries are indeed insane - I don't understand the scenario that would be required for a no-knock entry to be the only acceptable option. Are the police scared of the occupants firing guns at them? That would be ironic.

[cperciva]

I don't understand the scenario that would be required for a no-knock entry to be the only acceptable option.

The classic example is if the police think that evidence could be destroyed very quickly, e.g., electronic records.

[15155]

This is such a bullshit reason:

For one, you could detect these no-knocking individuals quite easily:

- Cameras on the exterior of the property

- Motion lights, motion sensors, motion bells are all quite cheap.

And re: destruction/obfuscation of electronic evidence-

-"One-click" destruction scripts, etc.

- TrueCrypt volumes, everywhere. Circuit breakers, power strips, etc. with switches. If you don't manage to destroy the volume, no aggressor will be able to access it.

- Degaussing setups for spinning disks, activated by similar mechanisms.

This stuff is pretty cheap, easily available. Anybody caught by these technically-incompetent police executing no-knock raids deserves to be caught.

Hell, if you don't have a few 6TB volumes full of random bits, labeled "Evidence," you aren't doing it right. Gotta tie up those investigative resources somehow.

[SamReidHughes]

What people could do doesn't matter, it's what they do do.

[XorNot]

Which would be exactly what's not happening if "a guy has a gun".

Either someone is in danger, in which case no-knock isn't needed, or they're not, in which case why the hell is a SWAT raid being carried out on the basis of an anonymous tip?

[Paradigma11]

A situation with hostages where the perp has already killed and is unaware that the police has arrived.