I kinda was thinking the same thing, but came to the conclusion that when they are ready to hit the caves by themselves, they will know it and will do so.
I agree.
I also think making minor mistakes (on your own) is one of the best ways to hone your technique. Getting the self awareness and cave awareness to know what's working and what is not is key to progress. What works for one diver (an instructor/mentor) may be a fruitless head banging exercise for another to try.