Around 12:43am on Tuesday, December 31, 2013 (UK time), Patrick O'Callaghan wrote:
Conclusion: better look for some other way to cover your tracks, and note that a forensic investigation can be carried out without having you log in at all.
Just to emphasise what Patrick says, if you boot Linux into singe user mode, you can get root access without needing a password, which would bypass any setup you had done this way.
You would be better off using disc encryption, and claiming that you used a long pass phrase which you had written down rather than remembered, and that you had destroyed the paper it was written on.
Steve