Well nothing can negate an incident like this, but a lot can be done to mitigate the damage and disincentive this happening in the future. The government that has jurisdiction should heavily fine the person(s) responsible and direct the money towards the victims in the tanker and for environmental cleanup.
I suspect that additional incentives wouldn't have changed anyone's behavior here. Nobody involved wanted to crash.
Of course not. But the owner of the yacht and/or possibly the person who the owner hired to manage the yacht deemed that the expected loss due to their negligence wasn't big enough to warrant being not-negligent. Adding punitive "environmental fines" might tip the balance.
It’s a good question. One answer could be “enough money to act as a deterrent” and “who cares, the govt I guess”.
EDIT: Could also do the student debt thing and have the fines pierce corporate veils and not be dismissible in bankruptcy.