Libertarians would not have limited BP's liability to the small amount Obama has (mind you, I was for Obama this past election). Instead, they could continue to sue and demand money until BP put enough resources into the problem to get it fixed. If BP kept avoiding payment, libertarians would attack BP more directly, possibly at the sources, without there being a US military (paid by those living in the gulf I might add) around to protect BP's assets. BP would have to hire its own security, the expenses of which would be directly proportional to how much they've pissed the world off. BP would be made an example of, and other oil companies would see how much of a liability it is to drill in the Gulf; a liability that currently doesn't exist because spills result in a slap on the wrist, and the government doing the cleanup. More so, the fine that BP paid comes out of the company profits, which come directly out of shareholders' stocks. Most of those shareholders are just people with mutual funds in their retirement accounts who had nothing to do with what happened. Libertarians wouldn't go after the corporate entity, they would go after those responsible directly. Again, no socialist government to stop them. Other companies, seeing the liability of drilling in the gulf (and having to pay for their own protection instead of making us do it) would raise their gas prices, making people rely on things like bicycles, public transportation, and electric trains and vehicles much more. As a result, there will be fewer emissions and destructive urban sprawl, since living 45 minute's drive from your job would be considered too expensive. And the gulf would be left alone, or at least very carefully maintained.

TL;DR You know how the trailer trash right-wingers vote against their own self interests, such as universal healthcare and fair wages, by voting for the republican party? That weird disconnect exists within environmentalists socialists (not using socialist in a derogatory way mind you) by voting for government that provides oil companies with free military protections, shelters the CEOs with corporate liability protections, and pays to clean up their messes.