At the risk of being down-voted, then I would imagine Most users of drive encryption software on windows have little to hide from GCHQ, and are simply using it to enhance the privacy of their personal information from casual eaves droppers such as PC repair men or after casual theft of a laptop / leaving it on a train. To use an analogy, not using encryption is a bit like sending personal information on a post card. It's not that a paper envelope is an impenetrable barrier to a determined snooper, but it stops casual loss of personal data. Therefore I suggest that most users of Truecrypt on windows do care about security (otherwise they wouldn't use it), but don't require government proof security. Horses for courses as they say.