While foreign honours are a hot button issue for Americans, particularly, I see things slightly differently from Joe McMillan.
I do see a grant of arms as an honour of sorts – although I am not sure whether arms that are registered, rather than granted, should be viewed in the same light.
(I am currently making an application to Pretoria for registration of my arms.)
But a coat of arms is certainly not a title of nobility.
There is no reason to deny a US citizen arms, whether granted in London, Edinburgh, Dublin, Ottawa or on the European Continent.
Republican registrations (state or private) should not be an issue either.
What I do find distasteful is a trend (among a minority in the US) to purchase dubious titles from self-proclaimed vendors, and then display nobiliary accoutrements with their arms.
This sort of self-aggrandizement is illegal in Scotland, but is nigh impossible to control anywhere else in the world.
Regards,
Mike