If all addresses are BCC'd, they don't appear anywhere in the recipient's e-mail headers, so there's no way for them to see the e-mail addresses. I just tried the Reply to All in Outlook on a few e-mails I've both sent out and received with BCC'd addresses and none of the hidden addresses appear. Only the To e-mail of the original sender.
Well, I wasn't worried about the addresses showing up, so much as... if you get a message with BCC addresses, and you reply with "reply all", does only the sender get the reply, or does everybody get the reply? (I could swear I remember reading a web book with an e-mail section that warned about that sort of thing.)
Edit: Yep, I did some googling, and I remembered right... there are several places that warn that if someone does a "reply to all" on a BCCd message, everyone will get the reply. Since many of our customers are competitors with each other, this would be a problem.

And Racx... don't you guys have summer school? There was a few times where I nearly failed a grade due to skipping school all the time (don't ask, it's a long story, I'll just say it had to do with depression), but I managed to just barely pass by taking summer school courses. Kinda sucked, but it's not like I had anything better to do with the summer months anyway.
Peace & Luv, Liz