You'll be surprised. Went to the Muv-Luv: Total Eclipse premier two years ago at AX and the crowd was chanting USA USA USA. The director said America was great and stuff and that sparked some patriotic behavior. Then we got to witness the OP and ED being performed live. More hollering, cheering ensued. The show was utter trash but the atmosphere made it seem great.
I went to 009 RE:CYBORG in a public setting and the director was there and explained that one of the characters was British. No chants of UK UK UK here, just a polite chuckle. But then again this wasn't an expo but the BFI which attracts, I dare say, the more high cultured crowd i.e. they were watching this film not because it was anime but because it was a foreign film.
I'll admit I may be considered a slightly self loathing anime fan i.e. snob in that if I see other anime fans I almost don't want anything to do with them. Though that's mostly because it's a medium and a broad one at that and I know two people liking anime doesn't necessarily mean they have anything in common and heck I certainly know my consumption of this medium differs widely from "the norm". And, heck, if you can tell someone likes anime from just looking at them it means they are either a) in cosplay b) wearing odd clothes like goggles c) buying Naruto manga. You'll never be able to discuss the intricacies of Inferno Cop with
those people so you're better off just walking away with your toffee nose in the air.
And the worst thing about it is that I've likely seen less anime, been watching it for less time and know less about it than them.