Going to throw my two cents in, since I'm currently not doing anything in FFXI. (go go boredom!)
Anyways, before playing this oh so wonderful game, I used to play Everquest. I mainly bring Everquest up because FFXI is very similiar to it, or at least as close as you can get without actually being Everquest.
On to my main point. In Everquest, it was considered extremely rude to "/check" someone's gear without asking beforehand. It was just the normal etiquette in that game. Personally, It didn't matter to me if people examined my gear on that game, but a majority of the Everquest population would get unhappy if you examined them.
Well, when I came to FFXI, I was amused that /checking was perfectly fine and normal. I thought it was better that way, to be honest. It was sort of aggravating being told you were going to be GM'd for accidently "right clicking" someone (In Everquest, right-clicking on the person would examine their gear). Most of all though, it made me wonder why people would get so worked up over something as trivial as being examined.
The answer was pretty obvious. People choose to get aggravated over something so trivial. It doesn't matter where you're from. It just depends on the person. If they choose to get worked up over it, just let them. Just as they can easily ignore the simple message, you can just as well ignore their reaction to your /checking them.
Now personally, I never /check people. If I want to /check someone, I always ask beforehand; Unless they have a bazaar, ofcourse. I don't really care what types of gear other people have. If I'm examined, I don't mind. It's pretty flattering actually. It means someone is curious about how you gear yourself.