Whether or not the college/university applied to accepts dual credit courses for transfer, the student is obligated to provide an academic transcript from that place. And for the rest of their life will have to order up a transcript whenever they apply to a grad program or for a job that requires all transcripts.
The parents in this particular school district need to work with the district and the community college in question and work toward a better tuition policy. Perhaps the tuition should be paid up front, and then waived later if the students stay at the CC. Perhaps there could be tuition scholarships for students whose families can’t afford the tuition (which is likely to be the reason for the classes currently being free up-front but paid for later).