One day I noticed that I was being a bit paranoid. Then I thought, "Hey, maybe that would be a good hobby." So now I'm paranoid. It's a hobby. It has nothing to do with wanting to become a prepper. Really.
My every day carry is informed by years of Dungeons and Dragons, because we all know how realistic the rules are. In D&D, you learn that the two most import tools you can have are rope and a knife. So I have a folding Buck knife and a woven braid of 15 feet of 770 paracord. In addition, I carry a small multi-tool, a flashlight, a lighter, a pen, and a small notebook. Of course, I also have my phone and my keys.
In case of pick pockets, I carry a $20 bill folded three times in my coin pocket. I've done a fair bit of research on pick pockets online. I have found two types of sites with information on pick pockets, which I call the ABC and XYZ sites. The ABC sites say that doing a, b, and c will stop pick pockets; but that x, y, and z are useless. The XYZ sites say that doing x, y, and z will stop pick pockets; but that a, b, and c are useless. I figure it's like stealing a bicycle: bolt cutters for cable locks, car jacks for U-locks. Different pick pockets have different skills, and you can't prepare for them all. Or the pick pockets are spreading lots of misinformation on line. Either way, I figure that I can't stop getting pick pocketed, so I prepare for having been pick pocketed. If that happens, I'll still have my $20 bill.
The first thing you have to understand about elevators is that they usually have a trap door in the ceiling. Why would you stand under a trap door? It's a perfect avenue of attack. So I always look for the trap door, and try to stand on the other side of the elevator. Elevators without trap doors in the ceiling make me nervous. I always assume they're there, but that they are subtly hidden. So I get in the elevator, assume they have sneakily place the trap door right above me, and move to the other side of the elevator. Of course, now that I've posted that on my web page, they're on to me. I'll have to change my strategy.
The doors are the next most obvious avenue of attack. You might think they're more obvious than subtly hidden trap doors in the ceiling. That's because you're not paranoid. So while on the elevator be in a ready stance facing the door.
Since you don't want people behind you, you want to be the last person to get off the elevator. Living in Silver Spring, I find this rather difficult. Everyone seems to want me to get off the elevator first. I didn't think I was that scary looking. My theory is that the DMV is so socially conservative that even someone as mildly odd as myself is seen as a significant threat. What a bunch of light weights.
I've been experimenting with different methods of not taking the same path each time I walk somewhere. At first I flipped a coin for each decision. While this gave me an excuse to walk around suavely flipping cool Sacagawea dollars, it turns out to be biased. If you have a three way choice, you have to break it down into two two-way choices. For example, if you could go left, straight, or right, you might break it down into left or straight, and then if straight go straight or right. But that gives you two chances to be straight.
Then I memorized a simple pseudo-random number generator that I could calculate in my head. Then I could use modular arithmetic to make decisions with different numbers of options. The numbers generated are correlated rather seriously, but it would take a large number of observations of decisions (done under different moduluses) to find the correlation, so I figured I'd notice the stalkers before they figured it out. The real problem with the PRNG approach is that you have to remember the state of the generator from one decision to the next, and there could be hours or even days between decisions. Paranoia is my hobby, not short term memory. I lost that to drug addiction.
So I started using Python to generate random numbers. It has a much better PRNG than I could ever memorize. I would write them down and mark them off as I used them. I also came up with the innovation of generating random numbers from 1 to 60 instead of 1 to 100. That way you can use modular arithmetic to make choices with 2, 3, 4, 5, or 6 options without bias. Note that if you use modular arithmetic on the numbers 1 to 100 modulus 3, you will slightly bias yourself to the first option. I lost the sheet of paper I was writing the numbers down on, and decided I was compromised. So I stopped doing that.
These days I just try to vary my routes by picking was to go that I don't remember using recently. This is going to be biased, based on the individual peculiarities of how my particular brain works. So someone could figure this out and trap me. But this is a subtle trick on my part. I'm actually trapping them, so the trap will become the trapped. And once I have them trapped, I will torture them mercilessly until they explain how my brain works.
I try to use situational awareness to notice threats both active and passive. This is mostly just paying attention to what is going on around you. This works well because it's not only paranoid, it's Zen. I'm pretty good at this when walking around, but not so good at them while sitting down. So that's when it's best to attack me. Or maybe that's just what I want you to think.
The first two points of sitting down everyone knows: sitting with your back to a corner, and sitting near the door. That way no one can sneak up on you, and you can get out quickly. The third point it took me a while to figure out: you want to sit near the back door. Trouble is probably going to come in through the front door, so if you're near the front door your escape will be blocked. Trouble does sometimes come through the back door, but that's usually because trouble is trying to be subtle. That will give a brief slice of time before trouble becomes unsubtle to slip on the back as trouble moves to the front.