Can't say that I've experienced anything like that Pete Zahut, I thought those machines just chugged their way through every number in sequence, which is why even ex-directory people get them.
When a person actually calls, I often string them along – for no other reason than it stops them conning someone else. I once had a call from “Microsoft Sever” telling me my computer was sending them error messages and they would help me correct them. After about ten minutes of me acting dumb, the guy was getting a bit exasperated, and said in his strong Indian accent, “I just need you to turn on your computer and I will show you”, to which I replied, “OK, OK I’ll do it right now. But there’s one thing I don’t understand, my computer’s an Apple Mac and doesn’t have any Microsoft software on it” – I had barely finished the sentence when he hung up.