A: You are correct that McKinney-Vento, as a federal law, supersedes state law, and a blanket policy like “Exclusion Day” cannot be applied to McKinney-Vento students. McKinney-Vento requires that districts review and revise policies to “remove barriers to the identification of homeless children and youths, and the enrollment and retention of homeless children and youths in schools in the State.” [42 U.S.C. §11432(g)(1)(I)]. Excluding these students creates a barrier and may prevent immediate enrollment and full participation under McKinney-Vento [42 U.S.C. §11434A(1)].
You’d want to look at each situation individually – if a family is simply refusing immunizations despite advocacy and support from the liaison, exclusion could be applied (although the family would also have access to medical, religious, or philosophical exemptions that exist in the district or state).