I support some residential users (professionally) and it would seem that some my older customers are not always the ones who are scammed. They may not be so computer-savvy, but they've been around the block a few times and know a scam when they get one. Some of the people I know who have been successfully duped are middle-aged professionals (who really should know better).
And they don't just get you by phoning you, like some spiders, they wait for you. A couple of years ago a customer of mine once bought AVG Antivirus from PC World, took it home and had trouble installing it. He told me that he rang PC World (from the number on the receipt, he said), got through to an indian call centre and they told him the reason he had trouble installing it was that he probably had viruses already. So they persuaded him to do a remote control session using teamviewer, and showed him all the "viruses" (in reality what they did was get him to start a command prompt, type "dir c:\ /s" or similar, which causes a long listing of all the files in the computer, and they typed something like "system error - system infected with viruses" or something. My customer couldn't see that until the very end of the listing when the words appeared as if by magic. To him, the computer looked like it was doing something very technical and ended with a scary warning about viruses). Then it got interesting. The Indian guy told him it would cost £300 to fix the computer. My customer, realising that something was not quite right, politely declined. Then the indian guy did something to his PC that caused it to never boot properly again (I couldn't work out what) and hung up, rudely.
When my customer rang me about this, he was adamant he had rung the number on the receipt. But after a bit of probing, he remembered that that didn't work and he did an internet search. Unfortunately, his computer had already been "got" by Ask Jeeves, and the first page of results were fake computer support companies. So he typed "AVG Support" and he got back a site which had a freephone number for what he thought was AVG support. They were possibly the Guruaid company, a well know scammer.
So he was duped by an ad. In his head, he was convinced he was speaking to PC World or AVG and he was convinced at first that he had rung the number on the receipt. I've had other customers duped the same way, when they're desperate for a number for BT or AOL or whatever tinpot broadband company they use, and they just find the wrong thing.
Oddly, I just typed "AVG Support" into google, and they appeared as an ad. Shame on google!
The outbound scammers can be very aggressive by the way - in one case they told a child that their mother was irresponsible and that they are going to remotely destroy their laptop!