I serve as an expert witness, and there are a variety of difficult ethical issues that being one presents, but whether you can say you’re not being paid when you are isn’t one of the difficult issues.
The case where experts allegedly were being paid when the jury was told they weren’t isn’t a patent case, but it’s interesting. At trial, the plaintiff’s lawyer allegedly told the jury that his experts weren’t being paid, but had volunteered out of concern for people injured by the product, a hip replacement device made by the defendant, J&J.
J&J loses, and it’s not just any loss, but a “bellwether” case — the first case in a series of cases, and so its outcome will affect the value of the rest of the cases. And it’s not just a loss, it’s a $500m judgment, reduced to “only” $150m under tort reform caps. And it’s not just a series of cases: there apparently 9,000 similar cases pending.
J&J has moved under 60(b) to set aside the judgment because, it asserts, in fact the experts knew they were going to be paid and were paid after trial, and a charitable donation was made. The case is on appeal in the Fifth Circuit, and there’s a longer story about it, here.