is it a bannable offence and why
Each case is unique so there are very rare cases where it is. If the other person is saying some toxic stuff while they spawn camp you, clipping and reporting will result in them getting a temp ban.
Other than those rare cases, spawn camping isn’t bannable. Every time you walk out the ferry doors you agree to PvP and the scuttle feature was added for a reason.
Keep it gameplay and there usually isn't a problem. Mix in audio beefing and that's opening yourself up to being held accountable for what you did or having it be used to manipulate the situation to make you look worse.
If you're into nonsense like spawn camping people doing certain parts of the new tall tales I wouldn't feel super confident about not having that turn into an issue for you
There is a lot of leniency in gameplay enforcement and there aren't a lot of people actually providing evidence that shows a clear issue. People that generally get nailed know what they are doing they just try to act innocent and like a victim after
Keep it clean and you'll typically be fine
The only real confirmed specifics I've seen in recent time from an employee is that if you just target one ship and hunt them on the server over and over just to mess with them they consider that an issue and will enforce on it if satisfactory evidence is submitted .