[Ryzorian]

They difuse in space. Sure they keep going but distance will difuse the effects. Otherwise the gamma ray burst from every explodeing star would vaporize us. ( Wich obviously they don't)

Plus the chances of hitting a freighter is slight, compareably speaking to say hitting a random planet or asteroid.

Mass drivers and anti matter weapons would more than likely be the big nasties...being able to convert a mass driver into an antimatter mass driver would be double points.