Thalassamania is exactly right. It'd be abused bigtime.
I know on the referral checkouts I do (these are rough numbers, but you get the idea) maybe 20% of the students coming in have been really prepared well, 65-70% are OK but not what I'd consider to be to the point on confidently nailing it first time on demand any time, and about 10-15% haven't even been shown all of the required pool skills or majorly regressed somehow between their pool sessions and the time I see them. That says to me that roughly only 20% of the instructors out there might really have their students prepared to walk into a one day session and nail it. It's all good to say it can work, but I think the reality is it really might make for even more poorly trained divers.
I know on the referral checkouts I do (these are rough numbers, but you get the idea) maybe 20% of the students coming in have been really prepared well, 65-70% are OK but not what I'd consider to be to the point on confidently nailing it first time on demand any time, and about 10-15% haven't even been shown all of the required pool skills or majorly regressed somehow between their pool sessions and the time I see them. That says to me that roughly only 20% of the instructors out there might really have their students prepared to walk into a one day session and nail it. It's all good to say it can work, but I think the reality is it really might make for even more poorly trained divers.