Hi Phil,
If I may jump in on this one - although I think it's already been answered pretty comprehensively anyway.
For me, self protection starts way before any physical confrontation. As Nick has already said, part of being aware is, not only being able to spot potential danger signs ahead of time, but also allows you to give out a subliminal "I'm switched on" attitude that will often be enough to remove us from the selection pool of any would-be attacker.
This is something we may never know has happened - but who cares, so long as we're less likely to be attacked in the first place, thats a bonus in my book.
Next, should someone get close enough to hurt you, then your level of awareness should have stepped up a gear. For example, if I'm walking around the shopping centre and there aren't too many people about then I would always try to walk with space around me. This means that anyway wanting to launch a surprised attack needs to get closer to me than anyone else around, which then begins to raise alarm bells.
If it's busier, then I will be more conscious of my personal space anyway, and will have more heightened state of awareness (if only slightly more heightened). I'm not talking here about walking around with your guard up or arms stretched out like a static zombie out of shaun of the dead. I just mean a little more alert mentally and more aware of everyone passing you by.
In the other extreme, when I'm in clubs where you're packed in like sardines, I would squeeze through crowds with at least one hand raised to my chin - which is this kind of space will go un-noticed, but means you already have a half guard and one arm raised closer to the jaw of anyone you may need to whack.
All I'm trying to say here is that, using you in-built self protection mechanism (intuition) and your conscious awareness techniques, it should be very difficult for someone to simply get to you without any warning whatsoever.
Even just walking towards someone you will see in their eyes, their body language, the walk, their breathing - what their intentions are. Even if they are consciously trying to hide the fact, they will be giving off tonnes of subliminal signals that your own intuition will pick up on. It's then your job to act on those intuitions rather than be the tough guy and over-ride them.
Having said all of that, it is still possible to get blind sides, jumped, etc. Whether that be the fact that we are so busy or pre-occupied with some other task or if we have simply let our guard/awareness down for a moment or two - we all make mistakes.
I've had several occasions where, working the door, I've been dealing with one incident and then been whacked or jumped on by other third parties.
When this happens, the only thing that will get you through this is your training. Sometimes there is no magic answer apart from being conditioned to take punches and instinctively fight back rather than cower with the shock.
My training, my animal days, my full out sparring with top people, is what has gotten me through all of these occasions. Someimtes there is simply no substitute for this.
The frequency of these occasions can be drastically reduced/albeit not completely eliminated, if you apply better awareness and avoidance strategies in the first place.
Awareness, Avoidance, Escape, Fence, Posture, Balloon, Aggression, Pre-emptive strike, Fight like F&*k - all are part of your self defence arsenal
Nice post by the way, good look with the training
Al