Slippers only @ work?

I think I've mentioned this before, but when you arrive at work, you change into your work slippers. No more heels for you, lady. Put on those slippers! These are meant to be worn only in school. Or at least that's what I thought. However, over the past several months, I have seen the other teachers walk outside, in the dirt and rain and all, to get to the cafeteria, then back into the school again. That defeats the purpose of even wearing these slippers. They're getting dirty when you walk outside. Don't you want to keep the school clean? Isn't that why you have this slipper rule?

I have accepted that we have to walk outside to get to the cafeteria. It would be too much of a hassle to have to change into your regular shoes every single time you leave the main building. So, I thought, these slippers are only meant for the campus grounds. This is also not the case. The other day, my co-teacher and one of the adminstrative dudes came to my apartment during lunchtime. As we left the main building, they didn't change their slippers! I asked, "Don't we have to change our shoes?" My co-teacher said, "You can if you want to." I felt wrong, so I changed into my regular shoes. They walked allll the way to my apartment, 5 minutes away, on the STREETS. Now, that really boggles my mind! These slippers are meant for school, not outside street walking! Why don't we just wear regular shoes then??