A: Actually, it's the opposite. Under the Fair Debt Collection Practices Act, FDCPA, debt collectors have strict guidelines for when and how they can communicate with you. If a debt collector leaves a message on your answering machine that even hints he's a collector, he's breaking the law. In that case, you can sue. Since debt collectors can't communicate with third-parties about your debt, they can't leave messages about your debt on answering machines that others have access to.
Keep in mind the FDCPA applies to third-party debt collectors not the original creditor.
ETA 9/4/07: A commenter referenced Foti v. NCO Fin. Sys., Inc, a New York court case in which the court ruled that answering machine message are considered communications. Under the FDCPA, § 806, 15 USC 1692d, (6), debt collectors must reveal their identities in communications to debtors.
Currently, the FDCPA, which was written pre-answering machines in 1977, does not have any guidelines about whether collectors can leave messages on answering machines. So depending on your attorney and the debt collectors attorney, a lawsuit could go either way.
Either attorney could argue that under § 804, 15 USC 1692b, (2) the debt collector cannot state the consumer owes a debt when communicating with any person other than the consumer. And under § 805, 15 USC 1692c, (b) debt collectors cannot communicate with certain third parties without prior consent from the consumer. The debt collector cannot guarantee that the consumer is the only person with access to the answering machine. If the collector reveals that a debt is owed in an answering machine message, there is the risk that a third party could overhear the message and learn the consumer has a debt. If this is the case, the consumer's rights under the FDCPA have been violated.