The First Unwritten Rule was: What Happens In Training, Stays In Training
Sometimes, when professor shows a simple or basic technique, some higher belts will skip drilling. They may think that this technique was done a hundred times before. What they don’t understand is that drilling simple techniques over and over again is what will make your game improve. Look at Judokas, they drill countless times basic throws to build up muscle memory.
In BJJ, there is always a detail that you may have missed that makes the whole difference in the technique. That’s why, however good you are, don’t be lazy, when the professor shows a technique, you should be an example for the lower belts and drill just like all the others. We can always learn something new about a basic technique.