Nope, they are going through everything. They wouldn't bother shooing you out of your homes if they weren't going to go in there! It's not just dusting: it's also maintenance and repair of things that get used frequently, shampooing of carpets,
However, the bots are deeply uninterested in your personal things, and will leave everything the way they found it (only sparkling clean) afterward. If you have any doomsday devices, however, let us know.