Recently I read that our inhibition on bikes when we are learning or even as we are, improving skills may stem from our in built gyroscopes. As kids & probably as cave men we learn that out limit of lean when walking, running or just reaching for something is about 20o. After that we fall over. Watching a learner or less confident rider that is about as far as they will go until teaching & experience re-programmes them. I know this was the case with my G/F. We did exercises which forced her to think of something different & she rode through this barrier without realising it. When she tried to do it consciously she couldn't. Oops, that's a bit random. As you were. I'm in the same boat getting other riders I know to join in. Some just outright say it's a waste of time, others have bikes that are too heavy & a few say they will give it a go but find reasons not to turn up. The guy I did my training with had to ride up onto the pavement to do a u-turn on an 8 mtr road at the beginning of the day. He finally managed to do it within the kerbs but has not practiced since. At least he turned up that day, 5 others didn't.