At our research facility, we make hypothesises and we test them. After some people expressed interested in the physical capabilities of the TurtleBot, we made some science happen.
Testing confirmed that the robot is capable of utilizing a elevator for translation in the vertical direction. Unexpectedly, the biggest problem was that the cliff sensors can trigger on the gap between the floor and the elevator. Additionally, the elevator car can act as a Faraday cage so teleoperation will be difficult. These are some things to watch out for if you are trying to get your robot to deliver lunch in an office building.
Also, not shown in the video is some payload testing where the robot was able to drive fairly well with a 10kg payload. Though it is important to make sure the robot is not top heavy and there should be an expectation of increased wear on the bearings which will decrease the robot's long term reliability.