They get around that by "customizing the motor oil according to customer needs on a person by person basis". In other words, you can't get a hold of their product by any conventional means. Neither will two people get the same product. I'm not an attorney, however, it seems to me that they are walking a fine legal line. I'm truly amazed at what some people think of when it comes to making money.
They don't need to go that far even and they already have won the case the way they conduct their business. They stay just below the threshold.
They routinely submit tests of their oil through recognized labs and nothing flags. They obviously have a customer base and done the "magazine testing" for publications so any claim of them being "illegitimate" would fall flat
They can easily challenge any technical point because the burden would be on the claimant- not them to show the oil was the root cause of the failure.
I have done lubrication litigation and arbitration for lubrication (claimed and alleged) related failure- they have the high ground, royal flush and S&W- all the plaintiff would have is a pair of 3's.