deadbeat
Rather than "no ring", I set mine for a "single beep".
That way, I know when they're calling, if I have the phone with me, but it's not loud enough to bother me if I'm in the next room.
I want to know when one of these dirtbags is calling me, so I don't accidentally answer, by opening the flip to place an outgoing call.
Whenever, I here the beep, I listen for the next tone, indicating that they've hung up and it's safe to use my phone again without being harassed.