That's exactly what we do as well. If I don't recognize the caller I hit delete. That's what I have caller ID for. Same as the landline we just let the unknowns go to the answering machine and 9 times out of 10 they hang up as soon as they hear the machine. We also have a "block" feature on the landline and use it a lot. Gotta love that one. If unknowns want to talk to me they'll leave a message and I call them back.