I do talk about saddles, i.e., even if you have a certain shape, it doesn't mean you need a certain saddle. We bring one of my bikes and one of DH's to show the difference in the cut out.
Again, there is a separate flat fixing session. It is hands on, but not for taking the wheel on/off. The church where we do this doesn't want 50 people bringing their bikes in the building, so they just bring a wheel.
I think the idea that "it shouldn't hurt to ride," is key.