for sure these are a potential aviation hazard but let's put that into perspective; We've had tens of thousands of RC aircraft flying around, some of them quite large, for the last three or four decades with very few safety incidents.
In the military context the legal rules of engagement are becoming more of an issue. None of us will weep for the latest victim but what when these become more widespread? How would we feel about, say, Turkey using one toeliminate a Suspected PKK member in UK?