I am thinking "Spill, baby, spill, is not so good a slogan.
I seemed to me that Palin saying "Drill, baby, drill" sounded rather sexual, coming from a woman.
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It is impossible to get ALL the oil from any well. They can get maybe 65% out of most wells. Thet can inject seawater, or steam and cause the heavier oil to come out, for example.
There is a cost factor involved, as with all minerals: if they cost more to extract than they are worth, it is better to just leave them where they are.