Yeah, I wish there were a special place in hell reserved for patent trolls, but undermining contracts retroactively is not something to be taken lightly.
Not sure that it would be undermining contracts retroactively.
IANAL, but the approach I'd consider is fraud/breach of contract. The previous victims settled and paid a royalty to use a patentable technology. It turns out that it was not what was represented. Ergo, refund. How it plays out surely depends a lot on regional courts, precedents, etc.
I wonder how air-tight you can make that reasoning. I suspect you could structure the settlement as paying to use the underlying technology _including_ the patents etc., rather than licensing the patent per se (so the fees paid are not directly predicated on the existence of a patent).
Be interesting to see how the courts would react to that though, and if they see it as a sign you are negotiating in bad faith.
It's not retroactive if you know about it ahead of time. It would be known when the contract is made that the money would by law have to be returned in the event the patent is invalidated.
The consequence would obviously be that all the licensees of a patent that has any chance of being invalid would subsequently try to get it invalidated so they can get their money back, but isn't that the intended result?
