IIRC a way which worked in Log1 was spawning a never-dying FX at runtime and detecting if it still existed, as they weren't restored by save/load cycles (but also going to the menu and change screen resolution, etc.).There's no way to detect when player loads the game as far as I know.
Not sure if the technique works in Log2,though, I can't try at this time (also because I don't know how to define a FX yet
)