I think it's more emissions related in North America and we have a different emissions standard then that of the EC [CE mainland]. Think zinc.
Incorrect according to the forums I'm reading all over europe. Some better threads are in Spain and France. Please keep in mind, many of the PD vehicles bought in europe are maintained by the concessionaire. A client drops his/her car off to their concession [dealership] and the service departemente performs the service under warranty. I found it rare to see new owners of a vehicle changing their own oil or doing any routine maintenance during the warranty period.
If there are issues with an engine usually it's dealt with at the level of the concessionaire and sometimes without the client being aware that there was a problem. Maybe many cams and followers were taken care of during a routine maintenance and quietly swept under the warranty mumble jumbo fine print upon the client receiving the keys to drive off.
"We're sorry it took us 3 days to get that special fitting madame."