Manufactures are not that bad. They know the law and so they won't ask for maintenance records unless that could be relevant. Many claims are rejected though because the wrong chemical (oil, coolant...) will cause failures which they know the symptoms - that is why they require specific records - they know that issues of a specific nature are often caused by not following maintenance schedules.
Of course it is in the manufactures interest to reject claims where they can. However it is also in their interest to pay out for claims since ease of handling issues is what builds loyalty.