Failure to prepare is not an excuse. There is a direct analog to "preparedness" here - when going on a long hike in the woods your don't get excused after getting lost because you forgot to bring a compass or map, or didn't bother to check the weather forecast.

That's what happened here. A few days before the spill the government announced intent to expand offshore drilling - in effect, they announced a hike in the woods. What we've discovered is that this walk was without compass, map, radio, etc.

The fact that there is nothing that can be done now does not excuse failure to prepare when there was opporunity.