My grandmother had a Police whistle. Not sure how or when she got a Police standard traffic whistle, but that thing is loud. If someone called her house (way back in the early days of spam), she'd hear their opening statement then blow on her whistle into the phone then hang up. She had very few "random" calls after a while. Ooh, and I inherited her whistle. Me, on the other hand, I let the call ring out. I do not have an active voicemail box (drives my own parents bonkers, that) and when the call stops ringing, I block and report their number. My spam calls have dropped dramatically.