You don't want to close the airport over nothing
But do you want to be the person that said "naah, there is no drone, no need to do anything"? So, yes, I can get their response. And to the "why no cell phone pictures?!" - person: do not assume everybody has a phone that can take a picture of a small object more than a few 10m away.... Most phones cannot, while you could still see and possibly identify the object. Phone cameras are optimised for a very different use.