BMW Warranty, who does burden of proof fall on?
So earlier this week, I purchased a CPO vehicle from a dealership that is over an hour away from me. The vehicle is also still covered under the factory BMW warranty. I noticed that the headlights were aimed far too low, so I took it to my local dealership to have a look. They informed me that the ball joints for auto-leveling of the headlights have popped out of their sockets in both headlights, and that both headlights will have to be replaced. They said that they couldn't cover this under warranty because they've seen problems like this in the past where it's caused by hitting a large pothole or other depression in the road. I asked if there was evidence that that a pothole was hit, and they said no. They said that there's usually a bent rim, or a bubble in the tire to indicate such an incident, but that I had none of these. They're reasoning was that the other dealership could have fixed the rim and tire before selling the vehicle. They provided no proof that I or anyone else for that matter caused this issue, and they could not say with absolute certainty that this was not a product defect in material or workmanship.
My question is this: Can they deny my warranty coverage of the headlights without proof of causation?
It seems that they're logic of "it could have been a pothole so we're not covering it" could be applied to just about anything. Without the burden of proof falling on the dealership, they could essentially decline every warranty repair request with crap like "it could have been a pothole". Am I wrong?
Note: The dealership that sold me this vehicle has already replaced both headlights. I'm just seeking the opinion of others, because I feel strongly that I should escalate the questionable actions of my local BMW dealership.