An article I came across today that reminded me of this thread. Kelly McCann is the shit.
Freedom From Fear: Spotting Trouble Before it Happens
By Kelly McCann aka "Jim Grover"
From Guns and Ammo
One of the most-asked questions during my street survival training is, "What am I going to see right before an attack?" That's a good question. It tells me the student is concerned about avoiding the situation altogether, and wants as much time as possible to maximize his chances of survival.
Those things you are most likely to see before an attack are called "pre-incident indicators." They are peculiar things you will recognize if you know what to look for. Any one of them alone is probably not enough to call out the cavalry, but when two or more appear, there is need for concern. If you pick up two or more of these indicators, take immediate steps to get out of the situation, place or activity in which you're involved.
The first indicator is unnatural impediment to your movement. It doesn't matter whether this is while you are walking, in your car or on a bicycle. When something stops you or causes you to go well out of your line of travel...beware.
Next is correlation of someone's movement to your own. When you first notice someone is keeping pace with you, it should alarm you. You stop, they stop. You speed up but the distance doesn't increase between you. The slim chance of two strangers regulating their pace so precisely is minuscule. Cross the street or go into a store. If the person stays with you, there may be something wrong.
Any sudden changes in status of a person(s) near you should make you think twice. For example, if you are walking along a city street and pass by two young adults who are leaning against a wall and they suddenly stop loitering and become pedestrians behind you, ask yourself why. What was it that made them decide to fall into step behind you? Regulate your pace differently and see if they are correlating to your movement. If they are, that's two indicators and a strong possibility exists that they have something much more dubious in store for you.
If you have been stopped unnaturally in your movement, or if you are standing somewhere and you notice predatory movements, immediately take some kind of action to extricate yourself. Predatory movements include circling, two people moving in opposite directions around you, or one or more people moving around or away from you and another moving at you.
A verbal exchange initiated by a stranger is unique enough today to make you take pause. People are much less apt to ask a stranger anything anymore. Attacks can sometimes be predicated on things such as, "Got a dollar?," "Do you know where. . ." or "What time is it?" Obviously, don't be ready to launch into the offensive when this occurs. Simply take a step back away from the person addressing you and look to the sides quickly. It is doubtful the person talking is the attacker; usually the attack is coming from the side.
Target glancing or avenue-of-escape glancing is a fairly reliable indicator that something is about to happen. This furtive glancing indicates the criminal is sizing you up, identifying escape routes, confirming there are no police in the area and so forth. This is noticeable when you see a person glancing in your direction several times, then glancing away.
If a person is approaching on an oblique path that will intersect with your own, you should beware. This is commonly used as an access route to the target because it keeps the attacker in a blind spot the longest.
Whenever an approaching person has his hand hidden, causing unnatural movement, keep an eye on him until either the hand comes clear of the cover or the person passes. Felons typically have their gun, knife or club already out when they approach their victim. To conceal it as long as possible on their approach, they hold it discreetly behind their arm or leg or inside their coat.
Any bump, shove or push should alarm you. It may be a pick-pocket attempt, it may be a setup, it may be just an impatient person. Whatever the case, if this occurs you need to be alert.
The relative absence of other people and authorities provides the criminal an excellent time to attack. Singularly, this indicator is not necessarily a big deal. When coupled with one or two other indicators it has enormous implications. Remember, an attacker strikes when it is least advantageous for you.
As you walk along there is another indicator of which you should be aware. Since the advent of drive-by shootings, most people notice cars that pull alongside them in traffic. As you're walking along, any automobile stopping alongside, slightly to the front or to the rear of you serves as ample warning to keep your eyes open. Any second pass of the same vehicle should likewise cause some concern.
You should also be wary of any obviously intoxicated person or group.
Have you ever noticed glances between strangers as they approach, impede, hail or otherwise interact with you? This occurs when criminals are just shy of launching their attack. They're looking at each other to ensure each is ready, taking one last quick look for cops, and glancing at the escape route to make sure it is clear. If the criminal is alone, it will look the same.
Any time you are confronted by more than one person and the first is in your face, keep your eyes not only on him but on the calmest appearing individual in a verbal altercation. Keep looking at the whole picture until you have to strike, then pick one target and strike.
Obvious attempts at baiting you are conducted only to cause a confrontation. Don't take the bait. Stay calm, keep your hands up and ready to strike or block, and keep moving. If there are other people in the area, move toward them and gain their attention.
Well, there you have it--some views of that picture seconds before something bad happens. As I said, any one of these things alone is probably not cause for concern; two or three of them should make you twinge with anticipation. If you wait any longer to act you'll be down to split seconds, and the chances of avoiding or surviving are exponentially decreased.
WHAT TO WATCH OUT FOR
Unnatural impediment to your movement
Correlation of someone's movement to your own.
Any sudden change in a person's status as you get near or pass them.
Predatory movements (circling, two or more people moving in opposite directions, etc.)
Any verbal exchange initiated by a stranger
Persons closing on you from an oblique angle that intersects with your path.
A hand hidden that causes unnatural movement by someone as they walk toward you.
Bumps, shoves, pushes or grabs
Relative absence of other people or authorities
Automobiles stopping alongside you or slightly to the front or rear as you walk along
Any obvious intoxicated person
Any second pass of a vehicle
Obvious attempts at baiting you
Glances between strangers as they approach, impede, hail or otherwise interact with you
The calmest-appearing individual in a verbal altercation; not always the guy in your face
(Kelly McCann has a series of DVDs called "Combatives for Street Survival" )