Watercolor - 11x15
I have taken many art classes and workshops over the last twenty five years and have taught classes myself for the last fifteen years and the one topic that is consistently the most controversial is 'Should the instructor paint on a student's artwork?' Every instructor has their own method of teaching - some prefer to give hands-on tutorials, others will demo an entire painting and a few will paint directly on a student's work.
Many students hate for the art teacher to paint on their personal piece - others don't mind at all. The advantage of this is you will see exactly what the instructor is teaching, you will have a tangible learning tool to take home with you and you will keep a piece of your instructor's talent. The disadvantage is that they can drastically change the style of your painting, your work does not feel like your own anymore and you can't sell you piece as your own.
As for my own teaching, I prefer to give a short demo at the beginning of class and then offer personal help throughout the class as the students work on their own artwork. As a rule, I never paint on their piece, preferring to let the student's individual artistic style emerge on its own. How do you feel about this?