I've seen several posting regarding forced subtitles. Those subs where the (let's say) the alien speaks in ultragalactic and we can seea subtitle with the english (or spanish, or french, or...)translation. What I do is to preview the movie with PowrDVD, and have a look at the subtitles options. Then I start DVDShrink, or DVD2one, and keep the subs as PowerDVD showed. Never fails (so far)
I ahvent had a problem with using DVD Shrink, deleting all of the subs, and the forced ones stay there, since it is not included when deletion of the normal subs occurs.