There is no timeline specified in the owners manual writings, correct?
It does not say damage will occur in 5 minutes/5 miles (or something to that effect), just that very serious and very expensive damage will occur.
A reasonable person will assume that damage will not occur instantly, and the specific doom language used is to instill fear into those customers that constantly bend the rules.
If, according to VW, serious and expensive damage will occur, and the dealer, knowingly or not, installs the wrong oil, then that dealer should offer lifetime free oil changes and an engine warranty to the original owner because there is no way to know just when that very serious and expensive damage will occur.
If using the wrong oil, for any length of time, will not cause damage, then there should be no problem with the dealer offering a lifetime engine warranty. That warranty should cover normal wear and tear, because there is no way to definitively know if that wear was initiated by the wrong oil, however long it was in the crankcase.
How can it be determined if 10% of the life expectancy of the engine was removed by the wrong oil? How can it be determined if nothing happened? How will the wrong oil affect future trade in or resale values? Based on the discussions here, I would never consider buying a used VW with the PD engine unless an extremely detailed oil change history was documented with dated receipts.
The vehicle owner should not have to prove anything.
The correct oil is specified, and the dealer installed the wrong stuff, as stated on the receipt (part numbers and/or total cost will show what type of oil was installed). If VW service records are maintained in a database, then VWoA will know that the wrong oil was installed, giving the ability to deny all future claims. Anyone that has had the wrong oil installed by the dealer has a potentially serious problem. They need something in writing, good at all dealers, that states that the engine warranty has not been voided due to the dealers negligence.
Dealers can change ownership. It is imparitive that any solution be good nationwide, and not tied to a specific named dealer.