I am lucky, my daughter goes to am school and was arranged pm session.
They don't really care. For eg: my friend has both his son's session clashed with school time. She has decided to give up going to the contest. She tried to call but the voice mail was full, she did not get to change to non school hours, .... She was quite angry though, she just have to 好無耐地 let go. I dont think she is ever going to enrol with this organization anymore.