The School Committee chairman says that more than a dozen callers complained about blood-alcohol tests at the school’s homecoming dance. The Providence Journal reported that chairman James Williamson said he does not understand why the policy drew complaints because students attending high school dances have been subjected to the tests for several years. Williamson said calls started Monday morning and he received more than a dozen by 11 a.m. It was not clear whether students, their parents. or others complained.