The glaring problem in your description of this event is the assumption that the object was a craft of some description......
This is the nub of it. IF they saw an actual craft or not. I cannot prove they did either way. However I do think they are credible witnesses and if they did it was something very unusual.
To put it another way, this is the most credible example of a possible sighting of alien technology that I can think of. That does'nt mean it is, but I'm prepared to entertain the possibility that it is.