Not necessarily. It could be that they no longer fulfilled the conditions that were in place at the time their study permit was issued. e.g. students who get admission into many schools, use one letter to get a visa and but their final destination is a different province or their answers to certain questions raised red flags or officer discovered an error in application of the law, or fraudulent documents, misrepresentation, etc.
One girl told us how came in with a 2 year student visa, but at Toronto airport I think she told the officers she would spend some time in Ottawa before travelling on to her final destination. The officer issued her study permit for 6 months and changed the expiry of her visa to 6 months too. She was told to apply for extension once she is in school. The only to get an extension would be to submit transcripts/admission letter and proof of enrollment after the first semester which shouldn't be a problem for a genuine student.