My rule for what can be produced in a public school artroom is cut and dry. The taxpayers are our patrons. They do not want to see students producing anything that is drug or sex related, or racist, or...(you fill in the blanks for your community's tolerance). We talk about the patronage system and how that relates to school budgets, art supplies and my job. I encourage freedom of expression, and will certainly support a student's right to produce whatever imagery they want with their own supplies, on their own time in their own studio. Over the past 30+ years I have never had a student question my logic. I have had students email images that they are working on at home for my critique, and will also work with students for portfolio preparations with work not produced in my classroom, so they know I am not censoring them.