This may seem obvious at first, but can be tough to pull off. But when done well, it is a really effective plot device. For example, the players know that demons from other dimensions are bad. Then have the PC's encounter more demons from the same dimension who have nothing to do with the first group. She assumed that all of the doubles were the same alignment as her, and most of them were.
People come looking for dead heroes.
Maybe not right away, but 007 was assigned any number of cases because another agent turned up dead, or failed to check in properly. If the hero escapes from the villains lair ignorant of his villainous plan, he's just another member of the opposition who has lost his cover. Gee Bond, we're glad you escaped Goldfinger's horse ranch hideout. Umm, not much really, he is involved in something called operation Grandslam, but I don't know what that is. This is what every villain goes for.