MirrorAshes, you wrote, "I've never heard anything even suggesting this was staged, has anyone else?"
Moore certainly has - here's a handy page, complete with tons of links, responding to lies that have been told about BFC:
http://www.michaelmoore.com/words/wackoattacko/Regarding the bank, from that same page:
The Truth: In the spring of 2001, I saw a real ad in a real newspaper in Michigan announcing a real promotion that this real bank had where they would give you a gun (as your up-front interest) for opening up a Certificate of Deposit account. They promoted this in publications all over the country – "More Bang for Your Buck!"
There was news coverage of this bank giving away guns, long before I even shot the scene there. The Chicago Sun Times wrote about how the bank would "hand you a gun" with the purchase of a CD. Those are the precise words used by a bank employee in the film.
When you see me going in to the bank and walking out with my new gun in "Bowling for Columbine" – that is exactly as it happened. Nothing was done out of the ordinary other than to phone ahead and ask permission to let me bring a camera in to film me opening up my account. I walked into that bank in northern Michigan for the first time ever on that day in June 2001, and, with cameras rolling, gave the bank teller $1,000 – and opened up a 20-year CD account. After you see me filling out the required federal forms ("How do you spell Caucasian?") – which I am filling out here for the first time – the bank manager faxed it to the bank's main office for them to do the background check. The bank is a licensed federal arms dealer and thus can have guns on the premises and do the instant background checks (the ATF's Federal Firearms database—which includes all federally approved gun dealers—lists North Country Bank with Federal Firearms License #4-38-153-01-5C-39922).