As the old saying goes, "the perfect is the enemy of the good". The all or nothing approach to anything can turn off the novice from even learning the basics, yet the basics can make a Uuuuuge difference in keeping away from danger.
-The old "stay away from stupid people doing stupid things at stupid places during ungodly hours", plus a dose of good old dumb luck will keep a majority of people out of trouble.
-The above, plus a good dose of situational awareness will keep one from trouble that the utterly oblivious will walk into.
-Add in actively thinking about risk, and constantly planning contingencies- where's my exit? Am I boxed in? Where's the weak points? What is that guy doing, and why? Why are all the people running in that direction? What should I do, and where should I go? Why is my door open?- things like this mean you can get away from trouble while not wasting valuable time.
Simple stuff like this doesn't need tons of training to do. Don't get me wrong, the more training you get, the better at it you will be. But every little bit helps.