Mustrum_Ridcully
Legend
Hardly. The difference is sizeable, perhaps, but it is easier (IMHO) to believe in a universe without monsters that can paralyze human-sized prey than to believe in a universe where you don't die unless you really, really want to. It is easier to suspend disbelief in the paralysis-proof game than the death-proof one.
I think one of the fundamental difference is: The "Death Flag" is not creating a universe where you can't die. It's creating a story in where your character doesn't die without the "author" agreeing with the possibility.
In the world, there is nothing preventing you from dying. But the story told about this world - and told through the game - doesn't involve your characters death until the point where the players wanted it to.
Most games do not have rules that tell us when a PC is angry, falls in love or wants to recite a poem. This is left as decision for the player. In a Death Flag game, the decision to die is also up to the player. Yes, that is a step far further then the aforementioned example, but it's still a similar principle. (And realistically speaking, how further is it? People in the real world don't get to decide when the fall in love, yet player can decide this about their characters!)
Because there is more to RPGs then just the story-telling. But sometimes the story-telling is more important then the other aspects. Role-Playing Games are a unique mix of several aspects. Different people just prioritize different aspects - and don't expect this priorities to be always the same for the same person, either.Then why have dice or mechanics? Why not just tie a towel around your shoulders and pretend to fight imaginary monsters?
Since I missed it the first time, I am not sure I am not lazy enough to miss it the second time...The answer I gave is upthread.

Some games would try to have the PCs experience the same risks Bond does. Some games would try to have the players experience the same stories Bond does.Some people think that a good James Bond RPG should allow the players to have their PCs experience the same risk that Bond does.
And some people want a mix of both. If a game would really create the same risks Bonds has, the way you'd played Bond would look very different on how he looks on screen.
An example for such experiences my players told me about was Call of Cthulhu - either play resulted in no longer being invested in your PC, or being invested enough that you tried to get the biggest guns and most effective combat abilities so you at least had a slight chance to survive the horrors.
If you'd expect a "regular" horror game where the characters are unaware of the horrors until they are confronted with them, and worry more about running away then shooting, this creates a disconnect between what you desired from the story and atmosphere and what using the rules as a model for the fictional reality leads you to play.
In a way, CoC is the opposite end of the narrative spectrum here - we don't expect characters to survive or keep their sanity - we actually fully expect them to die horribly or end in an asylum - or both, and feeling nearly helpless against the horrors of this world (or the world beyond). Using the "simulation" of the world though, we end with paranoid characters armed with heavy weapons acting very violently... (well, at least we got the insanity part right - but what happened to the reporter that just ends up babbling some incoherent thoughts?)
Medusas and Bodaks without a warning or context are very similar! The DM didn't communicate the risk that could have allowed the PCs to figure out a counter-measure. In a "Death Flag" game, a DM apparently hasn't communicated that he doesn't expect the players to make unreasonable actions (or didn't define "unreasonable" well enough for them to get it.)Because lava bathing highlights the problem with survival-guaranteed mechanics, whereas the problem with SoD is, IMHO, the universal one with all rules: if DM and player are not communicating well, the rules cannot save you.
And this errors in both cases can stem from the rulebooks not explaining its mechanic well enough.
"If you use save or die, remember that the PCs are expected to have at least some chance to predict the danger and create a protection against it. Of course, the chance and the difficulty depends on your estimation of the players and their characters abilities."
"If you use the Death Flag, all players should remember to act reasonably and avoid situations that shouldn't leave another end result as the characters death. Of course, reasonable depends on a mix of common sense and the group preference and can thus vary for different groups."
Suddenly, Save or Die doesn't look like such a bad mechanic too me, if it comes with this big qualifier. There would probably "more" to it - I wouldn't, for example, give a Medusa a Challenge Rating usable in a combat encounter, but a level for its "Quest" difficulty, or any other rating that helps me using it effectively inside an adventure, and not just in an encounter.