If your attack vector is adversaries ready to deep freeze your laptop, perhaps you should do your computing in a more secure location :)
The killcord would have been useful for Ross Ulbricht (Silk Road) who was busted by the FBI after using his laptop in public - they grabbed it while he had it unlocked and didn't have time to put it in suspend.
I’d really love a citation on this, especially since “quickly” seems to imply that they’d do this out in the field.
No idea how long you have to power it back on afterwards, tens of minutes to a couple of hours probably.
That said, the proper "kill switch" operation would be to explicitly wipe the key from memory before powering off (if you want to power off instead of just locking).
I wonder what their approach to a laptop with poor serviceability would be. I think it would take me more than a minute to get physical access to the ram of some modern computers.
RAM is still one of the most accessible parts for most laptops & desktops.
Tablets and phones on the other hand make it much much harder.
That’s pretty smart by the FBI agents to wait until it was unlocked and sneak up and take it. If instead they stormed in guns drawn, all Ross had to do was close the lid and bye bye evidence.
Drone strikes hit and kill hundreds of targets each year. Some on as little intelligence as an IP address used to click a link in a tweet.