> It's not really about the offer being made on the basis of public information though, is it.
The fact that it's based on public information puts the valuation's reasonableness on a very strong foundation, and allows the defendant to be far more confident that their offer will actually exceed a fully-litigated award.
> If the eventual settlement is less than the original offer, then the plaintiff is liable for costs...
But only if the original offer is reasonable. The basis of public information just makes it easier to support the claim that the offer is in fact reasonable.
Does this mean that in the case that you're sued by a copyright troll you can offer to settle for $1 and then if they take it to court and get nothing at all (because they don't actually have a solid case) they're now responsible for all your legal fees as well? Because if so that seems like a good way to deal with copyright trolls, since it makes the risks a bit more symmetric.
If the eventual settlement is less than the original offer, then the plaintiff is liable for costs that occurred after the point the offer was made.
As far as copyright law goes, it seems almost sensible ...