When I was a kid my dad got a phone call (no caller ID back then, just a basic phone). My dad said "hello?" and there was a pause. Finally the other end said Hey, this is Milt." My dad had a good friend named Milt from Illinois, who visits us a lot in Wisconsin. "Milt" asks how the fishing was going, the weather, etc for a minute or so. Then my dad said "do you have a cold or something? Your voice sounds different or something. Maybe it's the phone." "Milt" says " You sound different too. I don't what it is Jim". My dad's names isn't Jim. Turns out another guy named Milt happened to dial our number. He also fishes, and apparent the "Jim" he was trying to reach does too. I'm sure in another minute if anyone started talking about family members by name a red flag would have gone up eventually for both of them.
Some time in the early 1980s: I'm lying in bed on a Saturday morning. The phone rings. I answer groggily. Me (groggily): "Hello?" Voice (Yelling): "Git yo white ass outta bed!" Me (groggily): "Wha?!" Voice: "Kevin?" Me (groggily): "No" Voice: "Shit" (hangs up).