I was at a golf tournament a few years back and I can't recall how "the rule" came up, maybe someone hit a duff short of the tees, but someone in our group joked about "the rule" in the presence of two female volunteers. These were younger ladies that worked for me so when they asked what "the rule" was I passed on telling them, as I tend not to make off colour jokes/comments like that to employees. I said something like "you don't want to know" and every one in our group continued to make jokes about "the rule" with out saying what it was.
As the day passed every one was drinking and having a good time and I guess these ladies kept joking around about the ladies tee rule without ever knowing what it was. As they told me later at dinner, a rather drunk guy tee shot was short of the ladies tee and when they joked about "the rule" he
showed
them what it was. Lucky for him they were good sports, but they did give me a hard time about not warning them.