They were sending messages under duress.
With our kids we had a code word in case someone ever had to pick them up from school or something - they had to say the code word for the kids to get in the car with them (other than grandma or one trusted neighbor).
It would be a bad idea to have a code word to call the cops too. Although I probably don’t have to worry about a home invasion and then wait until the bank opens to get to my safe-deposit box. “Um - what do you want with my birth certificate and a will that is 25 years out-of-date for?”
I wonder if my kids would be smart enough to figure out if I dropped the code word into a phone call?
“Hey kids - why don’t you go over to grandma’s after school. I have to pick up a friend from the airport that is flying in from Khatmandu.”