Kept my old phone number after moving to a new area code. Very helpful as I just ignore all calls to the phones area code.
The wrinkle is that a very few people still don’t have free long distance so they are reluctant to call. My dry cleaners around the corner failed to call me because it wasn’t a local call.
Our library system needs to migrate into this century. 95% of the phone numbers we are given as part of our library card application are out of state cell phone numbers. The state government phone system doesn’t allow out of state calling and will not connect those numbers if we need to call them.
I understand the reasoning but yeah it’s pretty dumb considering how people keeping their area code/phone number after they move is quite common. Hell my parents even have a landline with a Colorado number and they live in Houston.
I dunno if there are blocks for this sort of thing, but when I ran a SIP based telephony service it was just a field (can’t remember something like CID, been many years) that you could literally put any number that fit. You could find plenty of PSTN termination services who would accept that also. We purchased numbers and assigned them to people, because the people we provided service to were actually interested in making and receiving phonecalls, not spamming.
I assume there are probably filters that at least want valid area codes and registered numbers nowadays, but the actual spoofing is trivially easy.
Summer 2019 some legislation went through that modified common carrier rules. Now telcos are allowed to refuse to connect calls based on point of origin and registration info.
There’s a whole registered subscriber system now, and a lot of mobile carriers just have an account setting that says “reject all calls that don’t pass registered subscriber verification”
Ever since I turned that feature on I now just get “legitimate” robo calls from fucking politicians, and 3rd party associates of places I do business with. The spoofed numbers are gone.
It’s government offices that have long distance calling intermittently blocked; maybe it was being abused early on, but was never fixed to be viable with more people retaining out of state cell phones. Penny wise and pound foolish.