Ovinomancer
No flips for you!
I think that the cost to the GM for killing characters is a factor here, too. Loss of previous effort, requirement to incorporate replacement, etc. It's not just sentimentality for the players.I don't believe one has to go that far to see signs of GM sentimentality.
Everytime a GM has the opportunity to kill a PC and doesn't follow through is an example of GM sentimentality - the most obvious would be in combat.