Of course it's possible, but this isn't one of those things. Certain aspects of the systems are breathtakingly reported as "top secret" in the press, but the existence of sonar systems good at hearing and sifting noise to recognize that kind of sound is widely known. We know Coca Cola exists. Hell we know the ingredients, but we don't know the recipe.

One of the first things I imagine an incident commander would do would be to ask if anyone has anything like that. Any ships in the area, military or civilian or foreign hear/see anything that they know of. Sounds like he got that information soon. Does that mean the whole thing was a waste of time?

Without knowing more about exactly what they did or didn't do, I can't say. And whether they should have done all of this is besides the point. They decided to do a search. And until they could connect that sound with the vessel, they needed to keep looking.

This is why stupid people doing stupid shit isn't just a Darwin Award situation. Search and rescue types don't want to stop until they succeed and you're putting them at risk too. They leave bodies on Everest, I would hope this was only ever just to confirm they were dead and no one was going down there but who knows.