There is an XML value that is supposed to toggle whether or not allied units take damage as well from this splash, but last I heard it was broken and I don't know if it was ever fixed in either fork. However, many attacks with splashes should have the splashes. For example, you throw a huge stone at a group of units where there is both enemies and your own units. You might hit your own units too, and obviously, that's gonna hurt. Splash does add a bit more strategy in the game. It can work against you or it can work for you. s