<local number, so I pick up>
Me: Hello.
<long pause>
Him (Indian accent, and probably VOIP): I'd like to speak to the owner of the house.
Me: Speaking.
<click>

I call back and the number is not in service.  VOIP, plus it's a spoofed local number.
OK, I've been harvested, for purposes unknown.

The phone system is becoming as hazardous as an internet connection without a firewall.  Suggested guidance:
1. If the number is not recognized, let the answering machine take the call.
2. If you must pick up, do not divulge ANY personal information whatsoever.  Instead, turn the call into YOU harvesting all the information you can about the caller.