I posted some comments that were lost when the servers were changed. I'll see if I can remember what I wrote.
I have heard-of and seen MB events that support both sides of this argument.
Some events have qualified instructors (MBCs) who present the material required, make sure to include everyone in discussion, make assignments to do things that can't be done in class, and track the completion of each scout and only sign blue cards for those who have earned them.
Some events have MBCs who either don't know the material, or don't know how to present it. They add to or subtract from the requirements. They sign blue cards for every boy who shows up regardless of his participation in discussions or his completion of the requirements.
I took my son to an Astronomy MB class taught at the local planetarium. When we arrived they handed him a worksheet (customized for the organization of the class), and sent him to find the answers to some parts from the displays. Then they put all the scouts (and their leaders) in the star theater. They presented information and had the boys write down parts of it, or pass it off with their leader, who then initialed the worksheet. This way, every boy had to be able to point out the constellations/stars/etc. They were able to set the clock in the star theater so that those requirements that normally take several days of observation could all be done in one morning. After the star show, planetarium staff went over the answers on the worksheets individually with each scout. Then the registered MBCs (there are 2 on staff at the planetarium) signed blue cards for those boys who had completed everything.
BYU, UVSC, and UNP Council co-sponsor an annual MB event using university resources (people, rooms, & equipment). All of their classes that I have observed are taught by well-qualified instructors. They have several assistants in each class, so that the boys can pass off individually and the main instructor doesn't have to individually do them all. They publish assignments ahead of class, so boys can come prepared with the things that won't be covered in the class room. They have sessions 2 weeks apart so boys can complete some assignments between sessions after some instuction has been given. They only sign blue cards if the boy has completed everything for the MB. Otherwise, the boy has to take his worksheets/notes/etc to another MBC to finish up.
I have taught several classes at district MB events. Classes are taught on 2 consecutive Saturdays. I make sure to discuss anything needed to complete out-of-class work during the week in between, and make assignments. I make sure to include everyone in discussions. I individually track who was there, who participated in discussions, and who completed outside assignments. I sign completed cards for only the boys who have earned them. Those who don't complete assignments or participate in discussions get partials. When(If) the boys come back to me to finish up, I concentrate discussion on those parts he needed to complete, but also briefly discuss the rest of the material to be sure he actually learned it.
I took my son to a one-day MB event. The Pulp & Paper MBC went over needed information (suggesting several times that they should take notes for when they want to pass off), demonstrated, and then helped the boys to make paper. At the end of class, he handed each boy his business card and said something like, 'call me when you are ready to pass off, or if you need help to make arrangements to do requirement 5 on your own.'
At the same one-day event mentioned above - The American Heritage MBC was surprised that only one boy came to class instead of the 10 registered. He waited half of his time for the other boys to show. My son had prepared some thoughts to discuss, but the MBC didn't want to discuss them. He wasn't willing to discuss American Heritage, only Black Heritage. He brought up several discussion ideas, but didn't follow through with any of them. In the end he suggested that my son should skip his other classes or come back on breaks to discuss parts of the MB. What a waste of time.
Again at the same one-day event - The Photography MBC came in late, spent about 20-minutes intruducing the needed information but not actually covering it, then said 'I told them it wouldn't take an hour'. He then looked at the assignment that my son had done (the only boy who had done it), encouraged everyone else to do it and find out more about photography, signed a blue card for everyone in the room, and dismissed early.
I accompanied my son to a Leatherwork class at summer camp. When we arrived, there were several boys sitting around, unsupervised, working on projects. The MBC (actually a youth staff member who was too young to be MBC) was sitting in the corner working on his own project and ignoring the group. When we disturbed him he said, 'go buy a kit in the traiding post, and show me when you are done.'
Eagle Scout 1987
OA Vigil Honor 1986
Fox - WE7-590-05-2
Currently - Troop/Team/Crew Advancement Chair & Dist Webmaster
Previously - SM, MC, CM, ACM, ADL, ASM, COR, Dist Camp Chair, PL, SPL, Scribe, Songleader, JASM, OA Chapter Officer, ...