Which is why you should use the security features that are built in, and not try to rig up your own. Because when you do, you'll spend a lot more time and effort, but you'll do a lousy job of it.
The security features in OS X (User accounts, the Guest account, Fast User Switching, Screensaver passwords) are built in. They're already there, you just turn them on and use them. Really, really, easy. You don't have to be a "robot" or a paranoid CIA agent. Just flip them on and forget them. All you have to remember is your password, which you have to remember anyway.
People seem to think that it must be easier to use bad security than to use good security. It must be easier to do it all yourself than to use what others have done for you. This is wrong. You'll end up as confused as the OP, trying to build from scratch what people have been working on for forty years now and wondering why it doesn't work right.
Hey, that's really nice and all, and I really appreciate the poor rep mark as well, especially considering that all I said was geared towards helping the OP achieve WHAT HE ASKED
. I never stated that he shouldn't take other measures, because perhaps he's already aware of those things.
My attitude in all of this is actually very neutral, and only meant to serve one purpose: to answer the OP's question. I didn't want to presume that he/she didn't already know about the password protected screen lock or similar features. I didn't even bother to ponder whether or not the OP would find it irritating to have to lock and unlock the screen every time they went to the bathroom, and neither did you apparently.
The question was specific and I answered it as such. And I'm not entirely sure that you should be speaking for someone else in terms of whether or not they'll do a good or bad job when it comes to 'rigging' their own security. In this case, it's not even rigging. You make it sound like there are hoops to jump through, where in fact it's a simple command line entry to get you from point A-B, and then up to you if it will suit your purposes.
You're mistaking different security measures for bad ones. Hardly the same. And yeah.. I actually DO understand the features you're speaking of. But it's hardly the point of what the OP was asking. The only dangerous attitude is that of one who thinks there's only one way to skin a cat.
Lastly, I never advised anyone to NOT use anything. Please don't create scenarios which aren't true. This is exactly why I feel the rep system can be abusive at times. People make things up which aren't true, and you get rep'd for it. But it's all good, see my Sig.