Switch to your preferred Unix-like OS (BSD or Solaris is probably better than Linux for this--most people have heard of Linux) but get rid KDE, GNOME or any other friendly desktop environment. Instead, run your preferred window manager (something that looks nothing like Windows or MacOS is better) and use xterms for all your actual interactions. Use lynx as your web browser and mutt as your mail client. (Or if you must use Firefox/Thunderbird, find the most outlandish and confusing theme and set of extensions you can find.)
Then, when somebody asks to use your laptop, just say "Sure, go ahead. This runs $FREE_OS, though, which may not be what you're used to." If they ask for help, tell them which man page they need to read to get the answer.
After three or four iterations of this, nobody will bother you anymore.
(Also, it's a good idea to set up a guest account and some way to to it, just in case you meet somebody who knows Unix. See other posts in this thread for more suggestions.)
I just downloaded it and played with it for a few minutes. Some comments:
The really nice thing about query-replace and query-replace-regexp is that you can replace almost all items. It's great for cases where, say, you want to replace all uses of variable "count" while leaving the word alone when it's used in a comment.
If you just want to replace everything, you use the non-query versions, replace-string and replace-regexp. That way, you don't need to hold down the 'y' key.
When I googled to see what the vi "." did, I found this, so the answer is no, but you can download an extension to do it.
But what I was going to say was that there are two options that I can think of:
Those two things, along with query-replace, automates most of my tasks for me.
Real Users find the one combination of bizarre input values that shuts down the system for days.