The point HoG Drama Desk and Dave are making about old school vs. new school is true for techniques, but it's also true for the approach to teaching. We had guys in the late 90s playing with leg entanglements, but a lot of coaches wouldn't show it to the newer students for liability reasons.
My instructors were black belts under Pedro Sauer back in the day, and they were very clear: you don't teach something that has a high risk of injury to someone who can't control their own body yet. That's still a sound approach, especially when you're thinking about retaining students and avoiding parent complaints. The "new" way for a lot of younger instructors seems to be throwing everything at the wall and seeing what sticks, without considering who is in front of them.