I will admit to masturbating in public restrooms and the women's room at work as well. I try to keep my moans and noise level as quiet as possible, but it is almost impossible to suppress a little pant or moan at climax.
I usually will use a finger or two, but I do have a small white pocket vibe I have used from time to time. It is pretty quiet, with a soft hum. It works better in my office when my office door is closed. Unfortuntately, I can't always close my door for those moments - hence the restroom break.
I have always assumed that other women do this as well. I am pretty sure I have heard a woman from another office on our floor "playing" as well, though we have never met.
I think I would be embarassed to be caught, though I do enjoy the voyeur aspect of it - kind of a contradiction, I know.
Amber