The OP later asks,
"I don’t doubt 1975. I am more interested in how they closed the door to people trying to escape. Was there actually a policy change in 1981?"
This is an important question. Especially for those currently studying, or non-JW family members who don't understand why former JWs are horrifically shunned.
I'm also interested in marking. What year did they add "marking", which goes right along with DA and DF status, and do they still practice it today?
Is/was marking for behaviors that threatened the spiritual cleanliness of the congregation, or rather a way to weed-out those who studied their bibles too closely and developed valid doctrinal questions like those Randy Watters reported from the '80s Bethel purge?
Both? When?