The same thing goes for those email offers you get of too-cheap-to-be-true product from overseas. The users are recruited over the Internet and are naieve.
When they call me, I tell them what they are doing is illegal and I don't usually hear from them for months at a time becasue as entertaining as it is, it's also frustrating and me telling them off ends the conversation real quick.
Yous are right, there are a lot of users out there who fall for this and might even feel their computer runs better after dropping $150 on a remote support deal.
There are also a lot of charges on your credit card statement for under a few dollars that you can't explain and don't bother following up, becasue it's only a few dollars and the description field is too cryptic to make sense to anybody or stand in a bank queue to work out.