A robotic chair that follows people around a library was the graduating project for a student at the Design Academy Eindhoven. The video below shows the concept chair activated using an access card and following a person around the library. Towards the end, the video also shows how a group of chairs could automatically be reconfigured to a particular formation upon a single user's command.



As noted earlier, this is not a working system but a concept demonstration. As it is noted on YouTube,

This is a concept. This model has a R/C remote controlled ?robot? inside.

Regardless, I think it is a cool idea. I also believe that we already have all the necessary technology to develop and deploy these robotic chairs. The technology developed for the museum tour-guide robots has already been demonstrated to work well in crowded spaces and it could be used to make these concept robot chairs into a real product.