RIAA sues LimeWire for $75,000,000,000,000

[Malthus]

If they had to pay 1% of this as a court fee (which is forfeited if they lose) they wouldn't come up with ridiculous stuff like that.

Read more carefully.
RIAA already won the case in summary judgment.  The ruling referred to in the OP was in connection with a separate trial on damages.  So a loser pays rule would not deter this as the RIAA already won.

Perhaps not a percentage court costs rule, but the "loser pays" rules in some places are more flexible than that - they can take into account the making of absurd claims that result in further litigation, even if one wins on liability. 

[The Minsky Moment]

Perhaps not a percentage court costs rule, but the "loser pays" rules in some places are more flexible than that - they can take into account the making of absurd claims that result in further litigation, even if one wins on liability.

That sounds dangerously vague to me. 

The position that the RIAA advanced was a plausible potential reading of the statute.  Certainly it wouldn't be the first nor the last time that Congress did something that could have an absurd result.

[Ideologue]

I wonder how much a "loser pays" system would chill socially valuable litigation?*  I understand that's the rationale for the American rule, but obviously it hasn't caused English rule countries to collapse in themselves or anything like that.

*Not a great deal of which is to be found this particular example, obviously.