I heard of some Universities were offering CPT from the first semester and you enroll only on online courses. That is illegal. USCIS has defined that to be a full time student you have to have a classroom experience. Only one online course counts towards your full-time status. One of those universities was raided last year in California and SEVIS record of all students were terminated. When there was complain about termination of SEVIS, USCIS said that students knew what they were getting into so there is no consideration. So be careful about such technical institutes.