I believe you'll find excellent customer service from all but the most bargain basement, low end optics (importers). I'm reasonably sure the profit margin on these optics is substantial so if a defective one is returned, it goes to the landfill and is replaced with a new scope or an ungraded model. They mnade their money on the original sale, a warranty replacement just puts them even up.
In fact, ot at least to my best understanding, all but the very specialized and insanely expensive optics are imported in their entirety or the major portion is (that includes Leupold) btw..
If the public really knew actual cost of hard goods, versus charged cost, there would be a revolt.
Far as I know, The only domestic glass polishers are in upper New York State and California and mere mortals can't afford either.