I warn in advance that I am not a lawyer. However, I have had occasion to be familiar with patent law and litigation. With regard to U.S. patent law, the difference between knowing violation and inadvertent violation of another's patent(s) is that treble damages are possible for the former (once proved) and not for the latter. A patent holder may well insist upon damages and might successfully sue to be awarded them once the violation is proved. For a time, an early employer had me reviewing electrical and electronic related patents soon after they were granted. I noted with amusement one which covered a combination of an incandescent lamp, battery cells, and a switch, all packaged in a convenient, hand-held container. The claims were sufficient to cover every flashlight that had been produced since Edison invented the light bulb. Yet I never heard of any attempt to enforce that patent, which would have been newsworthy for its ludicrousness. Many patents are either wholly or partially like the flashlight patent in that they are not at all novel or cover prior art. If patent examiners are doing their job, these would never be granted. The grant does not make the patent valid, but it can give the patent holder an opportunity to sue with hope of a settlement for nuisance value. If IBM thought their patent of something so obvious was remotely enforceable, I would expect we would have heard of them trying to extract money from some deep-pocketed users of the DB-access-via-web technology. I doubt they tried, but if they did, it would be amusing to see the would-be-defendant's lawyer's response.