Before we ban un-manned aircraft flying over populated areas because they keep dropping out of the sky, the following data would be required to support that:
How many manned aircraft are flying over say a period of 6/12 months, how many hours are they in the air and how many have been lost in the same period.
The same figures to be collated from the un-manned side off the house, then, once all the figures have been analysed you will have the percentage of failure rates for both manned and un-manned from the same statistical source and then you can bar the flying over populated areas of whichever has the higher failure rate until it improves to an acceptable level.