Scalado, the same software firm behind Rewind has announced a new app: Remove. Set to be shown off at the Mobile World Conference in Barcelona later this month, the application will let you remove people that you don't want from the frame. While Scalado hasn't immediately said what method they're using for this technology, the smart money is that it records a video or series of images, and then extrapolates which objects are in-motion, and allows you to remove them and replace the background.
However, that leads to the major caveat that's obliquely hinted at on the app's website "you can remove anyone moving around." So the person you're removing has to be moving themselves, which makes sense because otherwise there wouldn't be a background for it to reference.
If you're interested in moving and removing objects from a scene, but in a far more powerful way, Adobe has just shown off the new "content-aware move" feature of CS6, which looks like it'll give an unparalleled ability to recompose your scenes in post-processing.