My immediate reaction when reading that paragraph was that someone as security-minded as Aaron would probably not leave his password saved in a Skype client.
There's a difference between being security-minded and being a crypto-nut. If you're proud of the work you're doing and it's not secretive, why bother encrypting the hard-drive? Similarly, he wouldn't have been caught in the first place if he had been security-nutty about the process, but he didn't think he was doing anything immoral.
My immediate reaction when reading that paragraph was that someone as security-minded as Aaron would probably not leave his password saved in a Skype client.