Not a bad point. I don't carry a gun and none of the knives I regulary carry would be effective weapons, but a five dollar 6" Walmart chefs knife can sort that out. Use tape and cardboard to make a sheath and tape it down next to the seat of your car. Or tape the sheath to your leg inside your pants and rip out the lining of your pocket so you just have to reach into your pocket and pull out the knife. Instant access to an effective short term weapon. Alternatively a club can be improvised and hidden up the sleave of your jacket (if its cool enough to wear one). Weapons are easy to get a hold of if you think the situation will turn that direction.

As always keep your eyes out and avoid situations if you can. Keep enough distance between you and the car in front at a stop to drive around them. Windows rolled up or only down a couple inches (go ahead stick your hand in there, I've always wondered if my windows could take a hand off). Walking, be aware of your surroundings, keep an eye on where people are, where they're looking and what their hands are doing.
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A gentleman should always be able to break his fast in the manner of a gentleman where so ever he may find himself.--Good Omens