I've been getting the "V12214000332" caller ID. I think that identifies the caller as using a satellite phone (but the spoofing makes it impossible to know for sure). I bought a home phone that blocks 150 numbers but that is failing because the spammers are rotating their spoofed numbers more often. No point blocking one number when it will never be used again. Yesterday I got 5 spam calls for every one legitimate call.
It's knowing, deliberate harassment AFAIC... spoofing numbers is nothing more than covering their tracks and an acknowledgement that the call being placed is unwanted... likewise the strategies employed by those whose numbers are registered with nomorobo... place two nearly simultaneous calls to ensure the second gets through is specifically meant to defeat simultaneous ring.