I've noticed that debt collection agencies are beginning to put the burden back on the person. They have an automated line dialing a number several times a day, leaving recorded messages... Which, I guess, is fine. But the fact that I had to sit on hold for 10 minutes to inform them that they had the wrong number got irritating really quickly.
Perhaps I’m wrong, but I really don’t see this technique as helping an agency collect a debt. If I know I’m behind on a debt, and have no intention of collecting, then I’ll simply not answer the phone when the call comes in. And even if I answer, since the call is a recording, I’ll just not take the initiative to call them back.
On the other hand, I can see where it would help a company weed out wrong numbers quickly. I spent the time to call them, sit on hold, and inform them that they were repeatedly calling the wrong number.