Since our guys were gearing up for a counter strike, I think sitting vulnerable dead in the water to collect debris just outside 12 miles of Iran with Iranian gun boats probably looking for confrontation about, would not be the first priority. Second, finding some fragments drifting on the surface after the event wouldn’t be difficult, and they can drift into their waters by currents, or they could all be faked anyway. Having done lots of FONOPS in my earlier navy days, I am going to believe the Navy when it says the drone was legally in international airspace.
We have seen the drone ground track. These technological wonders have GPS on board and transmit their exact location hundreds of times per second. We are absolutely certain where the drone was when the transmission stopped. One could argue with the integrity of the reporting agency, but the track on the TV was clearly outside Iran’s claimed territorial water.
And while on the subject, how do we know that they l have the debris? When I worked on our drone program, we had charges that we could use to blow the sensitive stuff to smithereens. What do you want to bet that there are no collectible debris?