As a former crafts teacher for children, usually in a camp type setting, I can tell you that no matter what the project or the age of the participants, there are always those who could do two in the amount of time it takes the majority to do one of whatever it is, and also usually one or two who just don't finish in the allotted time. I would try to get my speed demons to help the slower ones, but that did not always work well especially with preteens!
Have not taken or taught any quilting classes, so can't address the issue you encountered.
It would seem that you must have been in classes that they did not indicate the experience level for the project &/or the desired outcome for the students.