I forget which game I played in the past where if someone used certain weapons (...was it nukes in Civ?), a diplomatic penalty occurred with all the other empires. I think Alpha Centauri did something similar with treaties...if you attacked someone without declaring war, everyone else gets displeased too.
You can probably see the point I'm getting to with Stellar Manipulations.
Oh, and to answer the first poster: I don't utilize that strategy because I follow a 'Geneva Conventions' kind of idea -- if the computer doesn't/can't use such weapons against me, I won't either.
zen