Sad to say but GM is a business - not a charity. The dealership is a separate business, that is serving as GM's agent in this matter. So if they're asking for proof of oil changes it's because GM is asking for them.
Yes, warranty repairs are regularly declined when there's evidence that the owner has not kept up their end of the warranty contract. But many more times it's approved, because owners understand their responsibility to look after their expensive automobile.
Here is an example of someone being denied on a 2013. As you'll read it took a while for the full story to come out. But GM called it the right way.
http://www.cruzetalk.com/forum/34-gen1-1-4l-turbo/151713-2013-1-4t-dexos1-kicking-my-hard.html
Yes, warranty repairs are regularly declined when there's evidence that the owner has not kept up their end of the warranty contract. But many more times it's approved, because owners understand their responsibility to look after their expensive automobile.
Here is an example of someone being denied on a 2013. As you'll read it took a while for the full story to come out. But GM called it the right way.
http://www.cruzetalk.com/forum/34-gen1-1-4l-turbo/151713-2013-1-4t-dexos1-kicking-my-hard.html