Remember, there is a person that you are dealing with on the other end of the line, just trying to make some money to get by.. and if you treat them badly, they may retaliate.
I spent several months working as a telemarketer, and whenever someone asked me nicely to put them on the do not call list....I would do it immediatly, often within seconds. When someone used profanity with me, or was a smartass...they were immediatly placed on a Multiple recall list, cycling their number up for someone to call several times a day. Do you really honestly think that someone that you have sworn at, or spoken to badly, or been sarcastic with is going to actually put you on the DNC List???. Remember you get further with a teaspoon of honey, then a bucket of gasoline
These people are usually herded like cattle into small call centers, paid less than minimum wage, and then given hefty bonuses for every sale they make, or any useful bit of info they can squeeze from a client. As long as minimum sles levels were met, a blind eye was turnedto wards people doing anything bad. And I worked for major call-centers for major companies, like Visa, Mastercard, Sears...etc, not rinky dink no-name companies.
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As well, there are now telemarketing companies that call from places other than North America, and therefore are not covered under USAs Do Not Call legislation. Only recently Canada (where a LOT of call centers exist, calling into the USA) started up a DNC list. Prior to this, we ere instructed to tell people that we had placed their number into the DNC....but nothing was actually done.