However, it is something every GM at pen'n'paper games was 'forced' to do from time to time. There's nothing worse than missing on the thrill of an encounter you ve planned way ahead, only b/c the players have become stronger than you expected. I find nothing wrong with that, nor my PCs the times I tell 'em I did it. Actually, they support my doing it.
There is no save/reload system in pnp. cRPG will be less flexible in that respect by default, as you already have a safety net, unless playing ironman.