Ramming - When does it constitute an attack?

[Anomander]

Since ramming isn't shown in server logs - You should make it somehow 'visible'
eg:
- Hey! would You mind stop hiting my ship?
- Oy! You scratch the paint
- That's enough, I swear if You hit me one again....
- You will pay for this - open fire!

If they keep bumping you tell them too stop.
If they don't make them into a blue message.

so basicaly ^this.

The problem is - what if You don't have enough firepower to destroy the ramming person.
And the ramming itself is a provocation / excuse to kill in act of 'defending yourself'.

Is timestamp + screen of You - telling to stop - is enough to sanction the guy?