Is there a whitelist feature so you can allow specific numbers that might be blocked to still get through this phone's blocking patterns?
Some people do expect to get calls from legitimate businesses that use 1-800 numbers in their Caller ID, which means scammers that impersonate those specific numbers can then get past the call blocker.
People who have to do business with businesses and the federal government offices located in Washington DC would have a lot of problems blocking the jerks impersonating the IRS, as those jerks make heavy use of 202 area code.