“There are people who will slap you on the back with one hand, and pick your pocket with the other.” That was the catchphrase of Racket Squad a syndicated TV series from the early 50’s. The show exposed how con men run their rackets. “Captain Braddock, Captain Braddock… ready.”
https://youtu.be/s_i5XdOnowU
Scams still abound, of course. I get calls every day on the landline with fake caller ID’s. Most don’t leave voice messages, but every so often there is one saying the IRS is investigating me and I must return the call immediately. Another trick is a fake Microsoft security alert message embedded in a Web page. The scammers are in India, with their English being, I suppose, a legacy of British colonial rule.