They can't assume the test will work. (The first attempt, at the Cassiope launch, didn't.) Crashes at sea are a lot less consequential than crashes on land.
(Flight paths are not an issue; they eventually expect to recover boosters from other space station cargo runs, which will follow the same trajectory.)
(Flight paths are not an issue; they eventually expect to recover boosters from other space station cargo runs, which will follow the same trajectory.)