We are now starting to use Absolute Black chain catcher on all roadbikes.
Absoluteblack chain catcher is designed to eliminate the possibility of chain falling in towards the frame when shifting to the inner chainring on uneven road. Chain catcher is a simple add-on component which improves the overall function of your drive train and protects your valuable frame from dropped chains. Especially recommended for Carbon frames.
Buy one to take with you on your own roadbike. 19 euro.