BellSouth’s DSL availability page will display the street address associated with any phone number that you enter, even if that number is unpublished or unlisted. I tried it with an unlisted number and it returned accurate information. How did I find out about this useful service? Someone who works for an ISP told me. I suspect it’s common knowledge among people who need to track down owners of unlisted numbers. It may be that this information is already available for purchase from data vendors, but if the phone company is giving it away it raises a number of concerns — privacy, of course, as well as questions about what exactly unlisted customers are paying extra for. It should be obvious that merely hiding the name on the account is of little value if the address is public.
So was this a programming oversight or does BellSouth really want to make all of its customers’ addresses public?