The majority of my robocalls come from a spoofed number with my same area code. Luckily, I happen to have an area code from several states away, so all my fake calls have out of state numbers. The odds that spammers spoof my local code is nearly 1:1000, so I am able to answer local numbers without issue. It is a less effective system post-covid because more people are using personal cells and VOIP to WFH.

Depending on the logistics, others might have similar success with a google voice number or the equivalent from a unique area code.