If you notice on the video, the way the chap fills the sink with the bucket, he's imparting a direction to the water, so it will spin whichever way he wants it to.
It exists, but only has an effect on weather systems, hurricanes etc.
Its a myth that water will flow in opposite directions depending what hemisphere you are in. I was on another forum and this was debated....So I tried it myself, and my bathroom sink flows in the opposite direction to my kitchen sink
The flow depends on sink bowl shape, which tap filled it, how long the water has been stood still, how the plug was lifted etc etc.
Do you honestly think that the coriolis effect, which does effect storms and weather patterns, will effect a small bowl 10ft either side of the equator?