No, it's not nearly that simple. The police find you holding a stick and big Eck lying on the ground blood pouring out of his head. You could say:
"I knew big Eck was after me and was going to assault and rob me so I brought my walking stick with me to defend myself" and that would mean you were carrying a weapon and you'd be going down.
Alternatively, you could say:
"I was walking along minding my own business when big Eck tried to assault and rob me, so I hit him over the head with the walking stick I happened to have with me to defend myself", and that would mean you would be much less likely to be seen to be carrying a weapon and you'd probably get away with it.
It's what you say, not what your intent was which makes the difference. Intent is extremely difficult to prove unless you voice it. I'm sure several Americans are howling with laughter at the absurdity of this.