content: I think the issue is that the drones were not just flying near the fires, but really close to where the helicopters needed to be. One drone from a similar incident was about four feet across, so they could be dealing with a similarly large drone this time. I assume they were worried about the drone crashing into their own craft, especially if it hit the rotors. I think if someone were flying a large rc craft of any kind -- for instance, one of those huge hobbyist jets -- they would have grounded their helicopter just like this time.