While I don't condone smoking pot, if the girl was doing her school work and fulfilling her duties to the team, I really don't think this warrants getting kicked off the team.
Right now, in many states is not a crime and yet at the same time in these same states employers make you take drug tests. Its all confusing. I live in Portland, ME, its legal up to a certain amount. And yet other public institutions will drug test you and deny you employment, or in the case of a student - financial aid.
Again, she knew the rules. But....