Silk Road founder Ross Ulbricht is currently serving multiple life terms in a high security federal penitentiary. He was captured in 2013 by law enforcement while using his laptop in a public library. Agents managed to distract him and grab his laptop before he could erase any of the incriminating information on it. If the BusKill had been available at the time he may have been able to avoid prison.
The BusKill is advertised as a "USB kill cord for your laptop." One end of the cord has a caribiner that attaches to your belt loop. The other end plugs into your laptop's USB and has a magnetic breakaway. If someone snatches your laptop and breaks the connection, the laptop's screen locks, making it harder for anyone to access your encrypted data. Optionally, you can set a trigger to shred the data. (If you use a data-shredding trigger you need to be super careful you don't forget you are tethered to it. If you stand up, it's bye-bye data!)