I would like to chime in, having instructed and raced for over 15 years.

I agree the reason we see so many folks signed off is the huge shortage of instructors we have at the schools. Most of the time, I see schools add more groups, which allows instructors to sign off someone, even though they may not be ready for the 'advanced' group. When I started this, there was the open group, and then the student group. It was up to the instructors to push, no that's too strong, nudge is better, nudge those who were slower to pick up the pace, and hold back the ones who may be fearless, dangerous, or trying to exceed their car's abilities. Hence the term, the 'instructor is the throttle'.

Now, schools just try to group folks together who are at a certian pace, and then let the more mature / safe ones run alone, to allow them to work with others, or have track time of their own.

Granted, there are always exceptions to the rule, I have had one person go from D student to instructor in one year. He got obscene amounts of track time (40+), he LISTENED to what people(other instructors) told him, he was VERY safe, observant, and courteous on the track. More importantly, being 270lbs and a pro rugby plaer from New Zealand, he commanded the respect of others, so he could be the 'throttle' in the car. He also finished in the top ten in his first race at Road ATlanta, in a car he had driven one other time, guy is crazy good.

Fact is, 30% of the time instructors aren't teaching students, they are baby sitting immature or irrational drivers, who without them, would get themselves into HUGE amounts of trouble. Most of us are smart enought to take care of ourselves, meaning we don't need a nanny service while on-track.