After getting only four calls from these people, I called them back asking who they were. Naturally, they began on their spiel about me being pre-approved for this and that. I lied by telling them I was only 16 and had just a Savings account. They told me I wasn't qualified and removed my number instantly -- they said it might take up to 48 hours to stop receiving calls, but after that call, I didn't receive another one, and it's been almost a week now.
If you think about it, they aren't going to want to mess with calling someone so young, not only because there's no business to be had (no Checking account, which apparently their entire platform thrives on), but also since doing so might put them into even more of a legally questionable position... even if they may think you're not telling the truth about being too young, they're probably going to choose not to take the risk of continuing their incessant calls.
Tell them to stop calling your teenage daughter, tell them you are a teenager, whatever you feel most comfortable doing (I'm 19 so this was easy to pass off -- it was only over the phone anyway). Sound friendly or at least indifferent, and be sure to emphasize that you don't have a Checking account either. If you get a persistent operator, simply hang up and call back, and you're almost certain to get someone new on the line. Above all, don't divulge ANY personal information other than the number you want removed (which they clearly had in the first place).
As a preventative measure in the future (and likewise to those who haven't been struck by this yet), add your number(s) to the National Do-Not-Call Registry at
http://www.donotcall.gov/ - this is GUARANTEED protection against these calls, but takes about a month to go into effect, so don't hesitate. These people WILL follow this list, because the consequences for not doing so are SEVERE. It's my gathering that violators can be fined up to $1,500 PER INFRACTION (and I believe an infraction would constitute a single call; correct me if I'm wrong). It'd also be very easy to prove violations -- all that would have to be done is a subpoena to a victim's phone company to find out when a call was placed, and then crosscheck that entry against the Do-Not-Call Registry's database of people who have opted out.
One last thing - the number they called me at is relatively new and has been given to very few, and only trustworthy sources. How they mined this number, I have no idea... sequential dialing sounds ridiculous, but it's the only thing seems even remotely plausible to me. I'm still curious about this phenomenon though, so if anyone has any idea where these people are getting phone lists, do tell.
Good luck to all!
-Ben (Lincoln, NE)
P.S. - For the sake of public knowledge, here are the four calls I received (yes, they called twice on Independence Day, and that's the same day I was removed):
July 3, 2006 @ 10:52 am - 888-669-8868 - Not answered
July 3, 2006 @ 4:55 pm - 888-669-8868 - Not answered
July 4, 2006 @ 10:18 am - 727-544-0057 - Not answered
July 4, 2006 @ 10:40 am - 727-450-0346 - Not answered