Nothing you can do about it. But they can go after the host. So the host can kill it off even if the person doesn't anyway. It'll get destroyed in the end.
In any case, I'm just happy Terra and Squall was confirmed. Too bad Rinoa wasn't, but I can see why, considering her weapon and her lack of any type of fighting skills.
What really pisses me off though, is no Ramza or Delita or Orlandu Cid. (I purposely put Ramza first as he's the one I wanted most from FFT. The other two however, can go either way.)