I am also curious, How do you know about the pioneer sister doing it for years and "it being undiscovered?"
I used too date 3 of them. No activity with me (I was sincere and young), but we remained friends through the years. One has traveled the world going to assemblies, preaching and witness group trips. Now she is over 40 (an old maid in the witness world). Last week she told me while in Europe about smoking pot and other wild activities. Locally, she has a main squeeze who is a MS. One is not a pioneer but again, has a companion at work that she dates regularly and is active with. The other told me of her activities many years ago when I was single, but now is very old and still very single. She mentioned of it happening only twice with others back then, but made a proposition nonetheless. She was the faithful pioneer sister who started prior to 1975.
While single (prior to marriage) I had the convertible car, on district assemby parts, started pioneering in 11th grade....yada, yada..yada. I made a lot of close friends, some still have trusted me with their secrets. Working the pioneer desk at an assembly as an 18 YO, sisters would offer me the invitation to help them with their time after work. I later found out many of these women were active in a very bad way. Most were DF.
While in HS I knew the prom was out. Many youths in my hall (4 congs.) went with worldly people and got hotel rooms. Some of the elders children were privately reproved. One elder forgot to take down his son's prom picture from his mantle as he did for (every bookstudy) over 10 months. Some considered it a coming out part never to return to a meeting. One of the latter was arrested during the 1992 LA riots and went to prision...and remains there.
Again, now as an adult, most couples are discovered after about 2-3 years. Some women that are friends of my wife are sexually active, but felt it was ok, because they married the man. I personally know of about 10 women that were active but married the man.
Private reproof was also used for favorites and elders children. They would not comment for a few months, but go to the Meeting for Service every weekend, only to make RV's alone, then get everything back after 3-4 months.