First of all... I understand that there are some work locations to which you can access only by walking on stage. For those cm´s, sorry, but bear with it: 10 more minutes on stage! *shrug* *wink*
Oh well... I have another point of view of why I don´t like seeing people wearing costumes or uniforms outside of their workplace.
When I was in school with the nuns, they didn´t allow us to wear our uniform after school hours and you would get in trouble if they saw you wearing it with sandals, another blouse, not well groomed at any store or private classes in the afternoon. As kids, it drove us nuts and we would do it on purpose.
Years passed and I started working for Hyatt which has almost the same policies for grooming that Disney does. They provided us with a laundry department and changing rooms to change clothes before and after the shift. Of course, due to budgetting, this changed later when they allowed you to take your uniform home and wash it yourself, meaning that some people would come and leave home already in costume. Then... another situation came... people were wandering in the stores and malls after shifts wearing the uniform uncomplete (no scarves, no nametags therefore holes in the blouse, sandals instead of shoes, etc, etc.).
I understood then why the nuns asked us not to wear the uniform out of school... it´s IMAGE what we are talking about! It costs a company a lot of money and efforts to build that image and it takes so little to ruin it...
An old costume wouldn´t look so bad among a lot of cm´s in their own workplace, but it would be a lot to comment by a stranger if seen in a grocery store, maybe with a coffee stain that the person wearing it just got on the way to the store. Did I make sense? I hope so!
In regards to Disney, I think that is one of the main reasons why cm´s in costume are given a locker... *wink*
I was never ashamed of saying where I worked at, but if I had to go out after work to any place, still wearing my uniform, I did it properly. I know not everybody does that, and that´s the risk for the company...