We've been crossing the border to play FRC for six years now, and to play VEX for the last three (usually to visit Rick and the Exothermic folks down in Redmond, NOT Seattle, right Rick?)... occasionally we have to leave a student behind because they aren't a Canadian citizen (yet). I can confirm that students, under the age of 18, travelling as part of a school group do not need a passport to cross the border, so long as they have proof of citizenship and government issued photo ID (a student card works fine). I can also confirm that students without proper documentation will not be allowed to cross the border.
Almost all our students have Canadian passports, however, and I encourage them to get them well in advance of robot season if they don't. It does make life easier. I take care of getting travel medical insurance for all of them... group rates are pretty cheap for young people on a short trip, and... well... I was going to say something about health insurance, but I understand that is a bit of touchy subject south of the 49th these days.
We have never had any problem driving across the border, unless you count an hour long wait coming home from Seattle on an Easter weekend a "problem". However we don't bring a trailer, and we do try to cross as a convoy, and while our documentation isn't quite as extensive as Travis has, that is mostly because we aren't carrying quite as much "stuff".
Oh... but do remember to mention to students that it isn't a good idea to cross the border if you have a criminal record as part of your trip planning.
We have never had a problem shipping our robot across the border, either, although there is additional paperwork involved. (And I'm crossing my fingers here, because our machine hasn't made it back from Seattle yet.)
So by and large, crossing the Canada/US border is a small hassle, but is likely perceived as a larger one by many teams thanks to the media attention and occasional, unfortunate, experiences that sometimes happen.
But back to the main point of the thread... I can add that the EASE of crossing the border has kept us AWAY from GTR, and for the past three years (ever since Seattle started up) we've found it much more affordable to compete with our friends two hours drive to the south than our friends five hour's flight to the east. Even the Portland regional is an inexpensive trip for us relative to GTR.
I know that the cost of getting out to Toronto has "worn down" some of the other FRC teams in Western Canada, to the point where we are the only ones left this year.
So when looking at 2006 vs 2010, you'll be missing four Western Canadian teams, two from Vancouver, and one each from Red Deer and Calgary, at GTR.
<edit: My apologies... the "death" of 1482 from Calgary has been greatly exaggerated. When I looked, earlier in season, they hadn't registered... but it appears they were, indeed at GTR this year.>
Jason
P.S. The BEST thing about crossing the border on the way home:
"Where have you been?"
"At a robot competition in Seattle."
"How long have you been away?"
"Three days."
"Anything to declare?"
"Yes sir... total purchases of $375.50, no alcohol or tobacco... AND THIS!" (holding up trophy)