I understand the policy in relation to warranty work in order to protect distribution of new lenses and I have no issue with it at all in that regard. Given the marginal savings on a new lens bought 'gray market' vs. the expense of repairs that would be covered under warranty, the mere refusal to honor the warranty is enough disincentive IMHO.
However, extending that policy to not locally repairing equipment even for a fee makes no sense. Why shouldn't I be able to buy a used lens anywhere and get it serviced by my local Nikon as long as it is an official Nikon lens? My view is that such a policy negatively impacts people who did not purchase new gray market lenses, those for instance that just move to the USA from another country with their equipment.
As I stated, this does not appear to be the policy (at least in practice) here in Canada.
Apparently Canon USA will service equipment from anywhere as long as it was sold by an official reseller regardless of gray market status.