Speech that "might start a fight" (abortion goes to school redux)

A recent post discussed a suit in which a middle school principal barred a student's anti-abortion leafletting. Another, similar case, also handled by the Alliance Defense Fund, was recently settled. There, the principal offered a potentially sturdier justification: such controversial materials "might start a fight." Yet this case was apparently still a loser for the school, probably because the danger was purely speculative. Whatever you make of the reliance in Poway on studies showing academic difficulties for LGBT students, the Poway school district was in fact being contemporaneously sued over severe anti-gay bullying. Though on the facts of Poway this didn't translate into a real threat of disruption from the mean-spirited t-shirt at issue -- the decision instead relied on the "rights of others" prong of Tinker -- this sort of existing, documented local problem of hostility between students over a particular issue illustrates the sort of situation that could justify censorship on the basis that student speech "might start a fight." (For more discussion of Poway, lotsa links here.)