Just for arguments sake... I still think the big point in what I've said here is that I only teach one or two students at a time. I believe that Instructors who do this regularly will side with me more than those who teach large groups.
I used to teach large groups... sometimes 10, 12 and even 14 students. If I was lucky, I'd have one divemaster - maybe two. As I read comments in this thread, it seems there are places where people are lucky enough to have several DM's to assist. I'm unaware of any shops in my area that can routinely provide a 1:1 or 2:1 ratio. 3/4:1 would be exceptional and 5/6:1 more the norm.
I have become accustomed to my 1:1 - 2:1 ratio by only offering private lessons. I think most instructors - event those dissenting from the 1 day checkout idea, would agree that private instruction allows for a much more intimate learning experience and students get so much more from it (assuming the Instructor is a good one.) In the pool, skills are learned in 1/10th the time it takes for an Instructor to complete 10 students. This makes simple, common sense. With 10 students, the Instructor has one student do the skill then moves on to the next... and by the time he has made his way around to 10 students... the first student has been twiddling their thumbs at the other end of the line.
The same time scenario plays out at the checkout dives when there are multiple students. It can take 10X longer to do 10 students than to do 1. Given this simple calculation, I can understand the arguments against doing everything in one day if checkouts contain only one Instructor and a multitude of students. You're right.
Consider the allowance of one day checkouts for private Instruction. Do any of you (my fellow Instructors) honestly believe you would be rushing a student or two (say a husband and wife) under any scenario where you completed their checkouts in one day? Now don't misunderstand my next sentence... I have completed my students checkouts the first day many times. They have completed all the required skills and done their first three dives. With that said, we always go back for the required second day just to play around (do a nice dive for dive number four.) We have to do this so that they can log their fourht checkout dive under the standards. This is the scenario I'm talking about. They rarely want to come back for a second day... They know they have met the requirements and feel comfortable with their skill levels... and I agree with them. The second day is just added expense and time away from them being able to do something else.
I'm not arguing this is right for everyone... because it is not. I'm saying it should be optional... because there are certainly siutations where it makes sense, does not cut anything from the training, the time involved with training or decrease the educational or enjoyment factors in any way.
I believe that if all students were taught in smaller class settings, retention in the industry would be higher. Have you ever considered this? How many people are convinced they don't like the sport 1/2 way into the first pool session? As they kneel on the bottom of the pool, shivering as they wait for 9 other people ( 2 or 3 of whom struggle) to clear thier masks. That's in an 80 degree pool. Now take the same group to the quarry in 50 degree water and replay the same scenario. How many more do you lose? Yes, we all know we certify them and we wonder where they go when we're done. You see, they decided they were done before you ever got them through the class.
Not because they lost their love for the sport... but because you gave them a miserable, long, drawn out experience that made them question - "Is this what diving really is?"
Some of you will say - "If they can't take it, then they shouldn't be diving anyway." That is not the right answer. If you're in the Northeast US or Pacific Northwest or anywhere else where the quarries are dark, dreary and cold... consider your retention rates if the days were not long and drawn out. It may seem I'm arguing against the one long day idea here... but just the opposite. The one day is not long and drawn out and when students see the light at the end of the tunnel on day one... they focus and get it done... they don't dread the thought of another long cold day tomorrow.
Just more food for thought...