What is the big goal here? To inspire a love of quilting, sewing, creativity? Or a perfect finished product? I would let the answer to that question guide you.
Most of us have experienced less than perfect projects - and we learned from them. Some of us learned how to cut, piece, press, quilt more carefully. Some of us learned we didn't really like this art form and moved on to something else. But we learned. And if we enjoyed it, we persevered - and our second project was better, and our third was better, etc.
To bring this full circle for the young ladies, you might talk with them about the process - what they liked, didn't like, struggled with, etc. If through that conversation you learn they struggled with the quilting, that might be a time to offer to add some.
Since they quilted them on their domestics, they may have had trouble maneuvering the quilt and are just happy to have it done.....and we also have to remember that our vision grows and develops with each project - maybe they just didn't know what else to do?
No matter what, you can be happy you have helped them with completing a project :-)