You are so right, Dennis.  The PREMISE might be they are offering a 'Free' Home Security System (which will never materialize) but then they 'need' your Credit Card # for "shipping" or "the monthly monitoring fee."  THAT's where they truly SCAM you.  All just elaborate RUSES to get CC#s, SS#s, or bank/utility account #s (which also give them access to LOTS of personal info, like your NAME, ADDRESS, BIRTHDATE & other such stuff for FULL IDENTITY THEFT.

As others have said, the only 'solution' is to not answer and to keep blocking numbers.
We do this and  yet we STILL get 4-8 calls DAILY.