I know this thread is old, but I'm going to comment anyway because I think this topic is really important.
This sort of thing didn't stop after the 70s and 80s, not everywhere anyway. My mother was baptised in 1992, when I was four years old, and I went through this and so did many kids in the hall I grew up in. The parents I knew who weren't beating their kids at the meetings were looked down on and other families didn't want to associate with them because their kids weren't "properly disciplined".
I'm going to try to get hold of a copy of this book.