not just in the household, but in the same town. Once a sim has found all the secret doors and pushed the statues around and cleared the rubble piles, those things stay that way for every other sim.
The biggest issue with WA is this: the tombs don't reset. there IS definitely an issue with replay value there, especially if you play the same town for a long period, as opposed to starting over frequently with a fresh game. That is, until you actually have explored every tomb. That type of gameplay really appeals to me Repetitive? Not any more than anything else in the Sims, and surely less repetitive than having your sim eat breakfast and go to work every day :O I was not expecting very much from WA, but I have to say I got completely sucked in and spent weeks exploring all the tombs (actually I think there's still a couple tomb parts in Egypt I haven't completed yet).