I get these calls all of the time.

I berate them. I tell them to do something meaningful with their lives and stop wasting space and valuable resources.

I do it in various ways. Sometimes I go "OH NO! A VIRUS!? What am I going to do?!?!...but seriously guy, you're not fooling me, get a fucking life." etc.

But that is not what happened there, the guy did not mess with them or bait them, he just did not comply because his bank warned him. So I guess this is even worse.

This sounds like a brilliant idea. I've got to try it. Especially since these guys usually try to prey on people they think are stupid.

If I ever encounter a scammer, despite how ludicrous it sounds, I see if I can get them to tell me about how the scam works. I'm not about to scam anybody myself, but I'm quite curious as to how they pull this stuff off, who they fool, and why they do it. Very rarely, you'll get the guy who's willing to spill it.
Otherwise, I just bait them into either wasting their time or giving me THEIR information to report them to the cops with.

Scammers using the threat of arrest and incarceration to coerce a victim to pay or comply? Sadly, they learned this tactic from the ones who invented this scam: government officials and law enforcement officers.

For email based scammers, mostly the 419/Advance Fee Fraud type: http://www.419eater.com/html/user_subs/interview/scammer_interview.htm

There is also a video by The Hoax Hotel on Youtube where he got a phone based scammer or two to spill the proverbial beans. I can't remember if the scammers in those videos were the Microsoft Fake Tech Support scammers or the Fake IRS scammers though. If I can remember which video it was then I'll link it here.

I heard recently some of those calls on youtube where people troll these Indian scammers. I was amazed those virus scammers even existed or that anyone on this planet could fall far it.
I wish we got those in Europe too, I'd troll them all the time.

How anyone fell for the 419 scam speaks poorly of our species.

I beleive he was from the American South.

Innkeepers get this one at least once a week:

Hello, I represent a group of missionaries from (insert country). We need booking at your establishment, all rooms, for 12 days this July. Please get back to me with a total. I will send you a check for the entire trip. You can deduct the cost of your lodging from this and please send us back the difference.

Greed kills brain...

I had an interesting one when I was still working as a receptionist 15 years ago. I once got a mail from the manager of a sports team from a country somewhere in the middle east (can't remember from where). He wanted to book rooms for the whole team (athletes, physiotherapists, trainer staff, ect.) for two weeks. He told me there was some tournament in a city 60 kilometers (~37 miles) away from our hotel, where they wanted to take part. Smells a bit fishy already? Well... The fishing cutter hit our lobby hard after some more mails!

When everything was worked out (including a small discount!), he mentioned another, little, completely unimportant detail... Since they were all from a middle east country, they couldn't just travel to our country freely. They needed someone in our country to vouch for them at the national authorities. Otherwise they wouldn't get their visas and couldn't go on their journey :-O Yeah, sure... Of course we'll vouch for 20 unknown dudes. And we're absolutely confident that you totally won't disappear as soon as you cross the European border! Thanks for the laugh, buddy. Try your luck elsewhere -.-

I don't know who or what this "manager of a sports team" was... We didn't vouch for them and the tournament he mentioned didn't exist. He probably just tried to find some idiots to help him getting illegal immigrants into the country.

That's probably what would have happened. And those people would never have shown up at your door (let alone with money...). Works after the same principle: "too good to be true"-opportunity, greed eats brain, you're duped.

I agree with this. It's the best solution for many similar cases too. :P

I've done this before as well.

But I try to shake it up and make it fun for myself. I'll tell them all my computers are running Linux (this tends to make then stop cold), I ask them which computer (I tell them I have three with different Windows versions) and when they identify a specific OS, I tell them I don't have that one installed on any of my PCs. I sometimes tell them to just fuck off, I sometimes say "Tell me something... does this scam work on a lot of people?" (they tend to hang up without answering). I try anything amusing that comes to mind just to make it a more positive experience for me.