Well, so far both Layla and Mr. Jack have agreed that it would be a sign of intelligent life.In other words, you would believe it was a random event and not a sign of intelligent life?
If it could be demonstrated not to be a hoax? I'd accept that as conclusive evidence of intelligent life.
Now, we need to figure out why they would believe that.I'd probably be inclined to believe it was intelligent life.
P.S. I would also agree it was definitive proof of intelligent life in outer space.