Earlier quoted context omitted.
Same thought here. I have been toying with the idea of building something OSS so that people could run it themselves, for this reason. (Also I have what is possibly a common filtering case in the US that would eliminate 95% of my spam calls without blocking any relevant calls from "new" numbers. And for whatever reason, I have not seen it implemented anywhere yet.)
IF (area code == my area code) AND (prefix == my prefix) AND (last 4 != my last 4) THEN SPAM SPAM SPAM ?
Also: if (area code == my area code) AND (number NOT IN whitelist)
Basically: I have a mobile number in an area I left 15 years ago. Any call I get from there that's not one of my friends is de facto spam.