Out Of Order

I don't know what made me think about this just now, but a couple of days ago, I was shopping at Ross (if you don't have Ross Stores in your area, imagine if TJ Maxx and Marshalls got together and had a learning-disabled child). Anyway, I went to try on a top in the dressing room, and two of the fitting room stalls had "Out of Order" signs on them.

How can a fitting room be "Out of Order?" I don't get it. Does the mirror make you look so fat that you won't want to buy their clothes?