Personally, I think Nikon should repair the equipment no matter where you purchased it. We have a global economy, and people travel. We can buy anything any where., and we should expect the manufacturer to stand behind their product. Nikon is not made in the USA. I bought many of my cameras overseas when I was in the Air Force. I didn't have the luxury of hopping a flight to the US if I wanted to buy a camera and lens, but I have a right to expect that the manufacturer has an obligation to repair the equipment in or out of warranty.

If you are concerned about gray market, what makes you think that at some point down the road, the next buyer or store that accepts it as a trade-in won't share your concern? Besides, as of April, it is doubtful that ANYONE outside of Nikon Melville or Nikon Los Angeles will no longer have access to parts, tools and training required to service Nikon gear. You may save some $$ intially, but later you'll take a beating when, and if, you sell it.

This is not about an "obsession" with gray market - it's more of a reality check. Refusing to reconcile facts contradicts a belief system will only get you in trouble.

https://petapixel.com/2019/12/10/nikon-is-shutting-down-its-authorized-repair-program-in-march-2020/

As far as what can happen to a lens (other than impact damage) that would require service - the following are things that have happened to lenses I have owned - many of them Nikkors, some Tamron, Tokina, and Sigma in the mix

oil on diaphragm leaves
broken switches
failed optical stabilization
failed focusing motor
broken AF/MF ring
wear affecting focus accuracy and reliability (lens mount, exceeding tolerances in AF mechanism)
scratch on front/rear element from improper cleaning
firmware upgrade
tight focus and zoom rings - requiring CLA (clean/lube/adjust) service
element fogging presumably from storing in camera bag that had vinyl on the inside that outgassed onto the lens surfaces
loose rubber grips on focus or zoom rings
excessive focus creep

These are just some of the things that have failed on my lenses over the past 53 yrs that I have relied on Nikon and others to repair. Imagine not being able to get it fixed - period! I have had friends that tried to get gray goods repaired by Nikon and it was a no-go.

Midwest Camera will NOT be able to fix a problem with your lens - if it can't get access to parts, tools, manuals, training. There is a chance that this is only temporary, especially when all the Nikon owners start making noise when their repairs start taking months instead of days, but I wouldn't count on it. I'd return the lens - I wouldn't want to have that headache down the road. . .