You are walking along when you see a suspicious looking character coming towards you. You adjust the hold on your umbrella or walking stick and prepare to defend yourself.
Aware of the need to protect yourself, as he approaches you suddenly hit out and break his head.
No! Bad! Very Bad!
The result? He lands up seriously sick in hospital.
And you end up seriously sick in jail!
Until proven otherwise, he is doing no wrong walking where he is. He has not at that point actually offered you harm. He is simply an innocent A.N.Other fully entitled to walk where he chooses, as long as it interferes with no-one.
You observe the possibility of an attack. Take several steps well to one side out of his direct path. If he simply continues on his way, on his original path, all well and good. No problem. He is (probably) not going to mug you.
But if now he changes direction towards you, the situation alters. You are under direct and immediate threat. You are in fear for your life. If you dont take command you will end up mugged or raped.
With your weapon at the ready that is, prepared to deliver an invisible attack into his...