In my best shoes I started falling forwards down the street

During workshops we always take our shoes off as we enter the room, so there is always a big jumble of shoes at the door. As people leave the room, for a bathroom break, to take a message, or even at tea time, they take the most convenient pair of shoes.
I am usually the trainer in this situation and always the foreigner so I leave the room last. In addition, I have fairly large feet, especially for a woman in Asia. As often as not, by the time I leave my shoes are gone, and only small sized shoes are left. Instead of my sturdy Birkenstocks or easy flipflops these are complicated affairs with straps, sequins and buckles, or little tight mens shoes with a (not so) small heel. After a quick search my shoes can be found outside the bathroom, soaking wet.
I've taken to hiding my shoes in corners or under my desk. I'd rather be barefoot.