The ultimate hotel UX fail.

Traveling is stressful and unpredictable, disruptive to our home life and circadian rhythms at the best of times.  Helping to minimize these effects is a key part of any hotel's value in its service of its guests. Sleep in particular is the primary purpose of any stay so anything that disrupts it is very bad for business.

Designing a hotel door hanger separately from the handle it goes on has just this kind of unintended consequence. Nothing wrong with having 'Do Not Disturb' printed on the reverse side of 'Clean' - as long as there is no ambiguity in which message is the guest's intention.  It's why a holistic approach to UX is so crucial to serving up choices and interactions that achieve the desired outcome.