I think the RNG is more to set what number the spammer appears to be calling/messaging from (caller ID spoofing). My current manager stated that if he gets a call from ‘interstate’ he ignores it on the assumption that it’s spam.
I block every spam number that calls or texts me, but have been getting a little worried about this practice because it is possible that while the number is currently being spoofed by a spammer it may belong to a real person or business and I will never be able to deal with them via mobile.
The US Federal Communications Commission (FCC, the same body that overturned Internet neutrality), is surprisingly enough pushing ahead with a plan to prevent caller ID spoofing (link is to press release PDF) by requiring telecommunications carriers to implement interoperable technology to prevent it. I understand that this will be in place by the end of 2019 - now we just need an Australian version.
Call spoofing is actually a much larger issue in the US, with a militarised police force. Swatting can result in police shooting first and asking questions later - because some kid got upset that he lost his online game!
