You are assuming that RNGs are always seeded with the current time, this needn't be the case, if you re-initialize a RNG with the same seed the output will be the same. And since RNG's are generators, (as described in my previous post) then if you keep track of how many times you've already called it you can hop ahead to that "place" in the sequence.
In the example in my previous post I'd seed the generator once (possibly with the current time) when the game is created (so when you click "new game"), then the seed would be put in the savegame and every time after that when you load a game the saved seed would used.
It seems that my point was misunderstood.
What I'm saying is that player actions are not the only thing that influence the RNG (see my NPC behavior example), so even if you loaded the same seed from the savegame, you may get different outcomes by just waiting a bit longer (might be seconds, might be milliseconds, depends on the number of NPCs / "ticking" objects on the map), as anything that needs to be randomized will change the state of the RNG and these events are not controlled by the player.
