They are indeed short sighted to use such a dirty trick even in this times, but honestly speaking, if just even one of the war lord is not being short sighted, then the land of Epirus would not be so chaotic and ununified for ages since the collapse of the Ottoman order in the region. Every one is just battling one another for a bit of interest or a tiny strip of land with little or no strategic planning for what that can happen in the future. Their eyes are mostly focused only on the lands of Epirus, they do form alliances, some times. But those alliances would always dissolve within a year or end up badly with one side stabbing the other in the back.