Fair point, I wasn't really thinking that one through at all. Of course it is still infringement both before and after purchase and the previous owner may have been just as likely to litigate as the previous one.

And I wasn't suggesting that a companies patents should become null and void after purchase, however my logic was still horribly flawed here. I really should avoid the internets when tired.

Although I do think, as I have stated elsewhere, that a right to a monopoly should not be treated the same as any other property asset and should maybe have some limits in transferability and stuff like that.