I don't see where the value of the life of a passenger vs a crew member comes into play. The issue is around training. I'm pretty sure that only lifeboats are mentioned during the passenger muster drill, I'll have to listen for this next time. I know for sure that they have not explained the steps in using a slide to evacuate the ship. I would hope that the crew is familiar with this method if this is what evacuation procedures require.
On the other hand, I don't recall if they explained this on
DCL, but I do know that on Cunard they recommend stepping off the ship rather than jumping, if one ends up needing to leave the ship w/o a lifeboat. You are supposed to use one hand to hold your nose and the other to hold your life jacket. I assume to avoid having the life jacket break your neck...
And based on what happened on the Costa Concordia, it does seem that you might end up having to make some difficult decisions anyway. So even if you are "meant" to be put into a lifeboat, a raft might be better then nothing.