Salinas, California

Got a missed call from 831?

A 831 number is not a red flag on its own — it is an ordinary geographic code for Salinas and the rest of California. But scammers routinely fake caller ID to match the first six digits of the number they are dialling, a trick called neighbour spoofing, so a familiar-looking code proves nothing about who is really calling.

If you were not expecting the call, let it ring through to voicemail. A real caller leaves a message. Do not call back to see who it was, and never confirm personal details to someone who rang you.

Worth knowing: an area code no longer tells you where someone is. Mobile numbers keep their original code when people move, so a 831 number may belong to someone who left California years ago.