A number of the sixth and seventh years complained that they’d never been told about this program and wanted to know why it had been kept a secret for so long. Petunia shrugged uncertainly, "I’m not sure for the exact reasons but given who was in charge here in the school until my arrival, is it any real surprise that this information was kept from you?" From the grumbles, it wasn’t a shock to anyone that Dumbledore wanted to suppress the knowledge that there were other options for schooling.