I do hope the following answer becomes mandatory reading for all Linden staff, so that Torley and others who, meaning well, quoted outdated information stating otherwise, will not in the future penalize honest people who only want more accounts for legitimate reasons, and are willing to pay for them.
Quoting Robin Linden's reply on 10/21/2006, in Linden Answers:
To my knowledge there are no more limits to the number of accounts people create, with or without a credit card. We *do* ask that people creating alt accounts pay us for the privilege after creating the first free account ($9.95 per alt account).
It's possible that someone has gotten caught up in the last vestiges of the original account limitations, so if you're having problems creating a new account please let us know. Maybe it's an error on our part.
It's also possible that someone has had problems (disciplinary or fiscal) with one of their accounts, and we *have* then limited them to the number they can have in total, which is consistent with the TOS.
It's possible that someone has gotten caught up in the last vestiges of the original account limitations, so if you're having problems creating a new account please let us know. Maybe it's an error on our part.
It's also possible that someone has had problems (disciplinary or fiscal) with one of their accounts, and we *have* then limited them to the number they can have in total, which is consistent with the TOS.
Since my request was originally started, the registration forms have added a box that requires a new registration to clearly state if this is their first account or not. While there is no apparent mechanisim to keep LL from being ripped off by those who lie about this or other registration information to obtain multiple free accounts, at least it does document that they did lie, if they are ever caught. And it appears that if one truthfully answers that they already have a free account, then the registration process does require paying for the new one. (I haven't yet verified that by attempting to make a new alt myself, but people have stated that they filled in the form truthfully to obtain an alt, and were billed for that alt.)
I would have liked to see an end to unlimited free unverified accounts as well, but that was not within the scope of my primary request, nor do any official Linden responses seem to indicate that there is any hope of eliminating the flood of unlimited free unverified accounts at any time soon.