Machinbird
For most operators UAS ist NOT a reportable item and therefore the NTSB would not know about it either. To write it in plain languague. UAS is existing in aviation since the introduction of speed measurement and has not been a real problem since the effects were (and I assume still are) part of basic training, starting very early in the training of the most basic aircraft. It is not over 50 cases, it is thousands of cases. But they were not reported since they are a non-event.