I had an Olympic distance triathlon swim get cut in half (from 1500 m to 750 m swim + a 1500 m beach run before transition 1) on the mere suspicion that conditions might be bad. The call was made the night before, and then in the morning it was still as glass. This event was run by the Iron Man company (World Triathlon Corporation), too.
I cannot fathom running a race in conditions that bad, especially that close to rocks.