I just watched a YouTube video of a Reunion Blues gig bag drop test - they dropped a cheap full hollow-body guitar off a four-story building. The drop knocked both pickups out and resulted in a crack in the top. Now, I'm not sure the result would have been any different if the guitar had been in a hard case, but the test doesn't exactly instill confidence.
LESSON TO BE LEARNED -- don't drop your instrument off a four-story building. Ever!