My DS (5) has told me that a TA told his table and others that their food would be removed if they hadn't eaten it within the next minute. DS is a slowish eater but he did eat his lunch, his friend although wanted to finish his lunch had it removed. They were late into lunch because the class was kept in to practice tidying up and sitting down properly. Ds said there was hardly any time to eat. Does this sound harsh or normal?