In ID4 (Independence Day), there are 3 helicopters sent up to greet the alien craft. One of the copters is fitted with a set of light panels that flash the lights in a specific pattern/sequence. What is the significance of this? Is this something made up for the movie or is the light pattern/sequence meaningful in real life?
I'm looking for an answer on why would they choose to do such a thing and not expect to be received as hostile.