[Rebelgecko]

Pretty much always, I think. The Black Swan Treasure is an interesting case. Peru, the US salvage company, and Spain all made cases for the treasure. It was found off the coast of Gibraltar, and Spain doesn't really agree with their borders/sovereignty. There were also allegedly some shenanigans involving the US State Department offering to facilitate the return of the treasure to Spain if Spain helped return a painting that had previously been stolen by Nazis.

[happy_path]

There were not "shenanigans", US doctrine is that the shipwreck belongs to the original country that fleet the ship.

[Rebelgecko]

I would consider the implied quid pro quo to be the "shenanigans"