Neither the U.S. Government nor private American scientists have any contractual nor treaty obligations to provide such forecasts. They do the best they can of their own free will as a global public service.
The way to protect against such such legal vultures is for the U.S. to simply abandon all attempts at prediction in any foreign areas.
This episode also illustrates the parasitic state that Europeans have sunk to. Not only do the Europeans expect the U.S. to protect them militarily and then whine about our "militarism", they also expect the U.S. to protect them with and to pay the cost of scientific forecasts of natural disasters in a part of the world that is mostly visited by European tourists.
Where is the European Union's Tsunami Warning System effort?
They're reinstalling it on a French aircraft carrier.
"Where is the European Union's Tsunami Warning System effort?"
Perhaps American victims should sue the EU for not having a tsunami warning system?