I wonder what it would take for a Roomba to detect such a condition and automatically avoid it. Some ideas:

- An internal sensor (photodiode) that would stop the Roomba if it got covered with some foreign material that interrupted a light source.

- A rear-facing camera that could detect if the Roomba was creating a trail of something behind it and stop the device. (Might not work very well on striped or patterned carpeting.)

- A forward-facing sensor that could detect objects such as dog poop in its path and initiate evasive action.