I've had to deal with a couple warranty issues at the dealer with my MK5. It's always a fight, it's always an argument, it always gets escalated to VWoA. I had both things covered, but damn, I don't want to fight for what I rightfully am entitled to every single time.
That's because dealerships make more money if work is not Warranty. Warranty coverage pays at a different, lesser rate, and less time given for the procedure (since car is new = no rusty bolts). If a customer comes in for some work, and there is no Warranty coverage, the dealership makes more money on those jobs.
Some dealerships are crooked and would rather make a few more dollars, so they would claim certain jobs, as not covered under Warranty. Once a customer escalates to VWofA, corporate talks to both sides about issue, and almost always sides with dealer.
I am a Tech, but don't work at VW. I suspect VW works the same as many other car brands, and dealerships. Some dealers are good and are satisfied doing Warranty coverage, because it pays well, and is steady work. Others want to make a little extra money.