I told you you'd like it...

The main problem with very expensive ties, as I see it, is that the tie you spend $80 on will be the one most likely to exert a magnetic attraction to soup, pens and other dangerous objects. The tie you bought for $10 at a discount joint? You'll have that one for years. Or maybe that's just my husband.

My Dear Robert, since you are an American, living in America, you can wear what you please...There are only a handful of expats here who could decipher your tie...You might notice that many Americans wear sports uniforms while not actually being a member of said team, or wear college shirts bearing the name of a college they did not attend.
While in the UK you might run across some who know the colours, and are members of the club/regiment/college etc., you will probably be given a pass on account of being a bloody yank...In modern Britain, they will know you're a yank because you'll be the only one wearing a tie with his track suit...

Basil nails it.

Me, I'm going to get a Queen's Own Oxfordshire Hussars in honor of Winston Churchill.

Generally, one does not wear a tie of an organization to which one is not a member. A caveat to that is that organizations which make a cravat's design very simple (e.g., yellow and red stripes) do bear the risk of nonmembers wearing it in ignorance. And once a tie is bought, it should be worn.
Stricter rules come from a bygone era when only few men wore ties.

For some reason I think their definition and my definition of a Gentlemen's Club are two very different things.

The Churchill dot rampant...

You might as well wear what you want, particularly if you have reasons as good as Colossus'.

What's the worst that could happen? After wearing the thing for five or six years, you finally run into someone who recognizes the pattern:

"Say, you're a CLH? Mountbatten's regiment, what? Awfully well preserved, chap."