This is exactly what I rant to people. Working IT support at a library where I sometimes help out patrons on public computers, it boggles my mind that many people still don't know how to do simple things like double-click or copy text.
We've changed our policy where we don't provide instructional services anymore, only tech support, because it would take up so much of our time trying to teach basic concepts.
Why not approach a local user group to offer to do tutorials one Saturday a month? I know a lot of guys at Linux user groups in particular would be willing to help... they may not like helping with mac/linux as much, but many would be happy to do so just the same.
We've changed our policy where we don't provide instructional services anymore, only tech support, because it would take up so much of our time trying to teach basic concepts.