UOAs certainly wouldn't hurt, but I doubt it's necessary for the average owner to go that far. The burden of proof will always be on the dealer or manufacturer that timely maintenance wasn't performed. If an owner can show documentation - even just a handwritten log - AND receipts for purchase of sufficient quantity oil to account for the log'd maintenance, it's not likely an arbitrator or judge would side with the manufacturer or dealer. I also happen to believe that if maintenance is performed according to the owner's manual's schedule in the service severity category applicable, it would be very unlikely to lead to an oil related failure (presuming use of the applicable viscosity grade and API or ACEA service category motor oil), anyway.
Excluding competition, how many oil-related failures occur during the warranty period to vehicles in which engine oil, oil filter, and air filter are changed according to the manufacturer's service and severity recommendations? And I'm taking into consideration the use of common, applicable service rated, dinasaur juice oils. Believe what you wish, wulimaster, but I'm not at all worried. (Why the unfounded paranoia?)