That's a shame some agencies are so lax. I'm going to jump of my soapbox now and just feel fortunate about the training I received.
Cavemn, help me understand why you think that is lax?
It makes sense to me. From a student point of view, s/he doesn't have to lay out a ton of money to take cavern & intro. The student learns the skills, practices them, dives within the certs, and decides if and when to make the outlay of funds to go full cave.
However, the student also has the right to go into training with doubles. The student HAS to show mastery of the skills AND doubles, so that the cave environment task load does not over tax the diver who is unfamiliar with doubles. So, the instructor evaluates, and gives the thumb up/down for training in doubles.
I don't see "lax" in any of this, because the choice the instructors' whether they allow doubles or require them.
Me, I'm really glad I had a year to practice after sidemount training before signing up for cavern / intro.