I have a rule for dealing with telemarketers - if they admit they're telemarketing right away, I'll nicely tell them I'm not interested. If they lie, then anything goes. Here's what happened to someone that called me from a "security company:"
Her: Is the business owner there?
Me: Are you telemarketing?
Her: No.
Me: Ok, this is the owner, how can I help you?
Her: Are you aware of the security threats faced by businesses that use the internet?
Me: Oh, yes, I'm well aware of threats. There are all sorts of threats when you're in business.
Her: Does your business use PCs?
Me: Security is a big problem, lawsuits.
Her: Ok, well, we offer a comprehensive...
Me: Because you know, you can be sued for all sorts of things. Employers can be sued by their employees. Business owners have to be very careful.
Her: (Trying to get back to her script) Yes, I'm aware of that. Well anyway, if your business is one of the millions...
Me: For instance, sexual harassment lawsuits, those are a huge concern if you're in business.
Her: I don't think that's ...
Me: Do you realize that people can sue their employer for harassment just because they receive unwanted sexual advances while at work?
Her: No, I didn't, but...
Me: (whispering) So... what are you wearing?