When I pretty much start the call by telling them that I have 18 years of desktop, server and network administration you would think that should scare them off, but no. They have a script to follow, and they'll follow it to the end of the Earth and over the edge. Most of the guys that I get tell me they work for Microsoft, and having worked on campus (and in fact having done security for a lot of those buildings) I find it amusing to take them on a mental tour of the Redmond campus. Eventually they drag me back onto the script. They're quite dogged, impressive in their own way.
About 30 seconds into one call I told the guy that I knew he was a scammer, and that he didn't work for MS. He still stayed on the line, doing his worst to try to get me to comply with his script, for another 23 minutes. The only reason that the call ended then was because it was time to toss stuff in the wok and I needed two hands.