After reading through an Ars article about the Ross Ulbricht trial, I came across an interesting tidbit on how they captured his computer and subsequent data:

http://arstechnica.com/tech-policy/2015/01/silk-road-trial-fbi-reveals-whats-on-ross-ulbrichts-computer-in-open-court/

"[His computer] was a prize so important they literally snatched it out from underneath him, before they even arrested Ulbricht."

I don't endorse or condone his actions, but I know if I were in his position I would be overly paranoid about security.

I had a Bluetooth remote button lying around so I threw together this tiny Bash script. If the Bluetooth device doesn't show up, the machine auto locks. You can change the device name to anything, such as your phone, so when the device goes out of range, your machine locks.

https://gist.github.com/anonymous/7b68595bb2021443f07d