sensei wrote: The original Japanese seiyuu are often performers and idols with huge followings, so probably they would be less approachable. But in the US anime is still a niche industry, and the people who work on it are much more like us, hardworking folks with a passion.
I disagree with most of this. There are a lot of Japanese seiyuu and artists who are just as enthusiastic about their job and their fans as the US voice actors. And I'd imagine that the same could be said about those who dub in different languages around the world. A lot of Japanese seiyuu are career seiyuu, and they need to continually line up jobs in order to pay their bills just like everyone else. Not only that, but many Japanese anime guests have sacrificed a lot to get where they are, or to have what they have. Although most fans are aware that most animators do not typically earn a lot of money, these fans many not realize that many of their beloved seiyuu/artists have not only had to put their lives on hold, but many of them have failed marriages or poor relationships with family members due to the time and energy each artist dedicates to their job.
When it comes to Japanese guests, my experience has been that the older the guest, the more appreciative they are of their fans. There are some exeptions, like Akemi Takada and Yuki Kajura, but guests who hit their prime more than a decade ago and many not have much in the way of employment now tend to show a lot of love to their US fans. The young pop stars and popular young seiyuu seem to be under the impression that there will always be plenty of work for them out there, or perhaps have not yet learned the finesse of fanbase maintenance. A lot of them just need to be humbled a few times and then you'll find that they'll be great guests to have around.
Most conventions try to solicit guests that fans are interested in, and those that the find also seem to love their fans and want to show them how much they appreciate their loyalty. I've been to conventions where artists will sketch for everyone in line, even if it means staying to sketch for hours past their scheduled autograph session (Mamoru Yokota & Hiroshi Nagahama stand out here) or despite their poor health (Izumi Matsumoto). Some Japanese guests enjoy partying with their fans (like FLOW and Halko Momoi), especially the fashion designer guests who seem to revel in the more intimate tea party gatherings that some conventions have.
I remember Tiffany Grant - I think she was at SakuraCon 2011. I'm not a US VA fan, so I never bothered to attend her panels, but I think it's nifty that she's offered to sign your poster for you.
I just got an email back from Tiffany Grant, whom I asked to sign a poster I won in the benefit auction at Otakon this year. It's a Rebuild of Eva 2.0 poster with five autographs, three of which are Shinji, Rei, and Mari but was painfully and sadly missing Asuka. This is the first time I've ever emailed a voice actor or anyone like this asking for an autograph so I really wasn't expecting much. The same day, I got an email back, in which she called me out because for some reason I had talked about Otakon like it was something she hasn't heard of and then told me shed be happy to sign my poster. For what it's worth, it just makes me feel good when I know the people behind the series I've grown up with and loved are just people too and don't mind taking a minute for the fans. That's enough out of me, though maybe ittd be fun if other people wanna share a similar moment or two to further reaffirm my love for our hobby 
