This is just a general opinion based upon general, not specific,
experience. I can't really comment in detail because I don't know
what
exactly you are trying to accomplish. As a general rule I believe
that
to the extent that anyone has local, physical access or even
proximity
to your system, you are in potential danger. If you really want a
lecture on the subject, may I suggest that you post to
http://www.openbsd.org. The subject has been discussed there
exhaustively, as they will tell you in no uncertain terms.