I have a neighbor with a lot of grandchildren. When these scams started he made each one of them make up a code word to be used if they were really in trouble.
A couple of months later I was talking to him and sure enough he had one of the scammers trying the scam using one of his grandchildren’s name. Didn’t work.
Reminds of a movie about a capture female officer set in WWII (or something similar.) The code phrase involved her admiration for dancing; however, she twisted the phrase enough to communicate she was under duress.