Yeah, tessa_morgan is right about the airflow thing. I tried a cheap one for a costume once and felt like I was being hugged by a boa constrictor. Spent the whole night taking tiny sips of air and wondering if my ribs would crack. Never again, I'll stick to clothes that let my lungs actually work.
Yikes, that's alarming. Do you know if she was trying to tighten it too much for an event or something? Those things can cut off your airflow if you're not careful. It's crazy how some people still wear them without knowing the risks. Was she okay after she fainted?