Yes, same results. Does damage but does not interrupt looting (I'm talking about arrows). I can't really test it with sword because it's very rare that a loot dot spawns right near the edge of a piece of land.

FYI, even if the the looter has .5 hp, the arrow will still kill him, but the death animation doesn't play because it still doesn't interrupt the looting (so said player will be holding up his loot, but he still drops bombs/arrows in the water as one does when you kill them).

The easiest way to test this is to spam arrows at someone looting near that island (assuming they're within range). Because they can only be damaged just before they pull up their loot.

Anyway, to sum up, people looting in water can still be damaged by arrows but it will not interrupt their looting. Perhaps whatever you did to fix this, you can do the same with swords and bombs (because like I said before, this is a much rarer occurrence, but it still happens).