Someone has already pointed out the Snopes article about the Coriolis force being too weak to determine draining directions, which is true.
But there's a second consideration - the Coriolis force varies as the sine of your latitude. It's tiny near the equator (this is why hurricane are unable to form at the equator) so you certainly wouldn't get a sharp transition as you walked over 0 degrees.
So, how is the scam achieved? You can pour the water 'off-center' so that it starts with some angular momentum. If you give it a small amount of angular momentum then it's not obvious before the plug is pulled, but the angular speed increases as the water flows towards the plug hole (the 'ballerina effect'). The guy putting the barrier in briefly won't necessarily remove the angular momentum of the water.
When they should the 0 degrees bowl and it drains 'straight' out it looks like maybe that bowl is shallower? That would help remove the initial angular momentum from an off-center pour. I'm less clear about how they're getting that one to work with no-circulation though.
But there's a second consideration - the Coriolis force varies as the sine of your latitude. It's tiny near the equator (this is why hurricane are unable to form at the equator) so you certainly wouldn't get a sharp transition as you walked over 0 degrees.
So, how is the scam achieved? You can pour the water 'off-center' so that it starts with some angular momentum. If you give it a small amount of angular momentum then it's not obvious before the plug is pulled, but the angular speed increases as the water flows towards the plug hole (the 'ballerina effect'). The guy putting the barrier in briefly won't necessarily remove the angular momentum of the water.
When they should the 0 degrees bowl and it drains 'straight' out it looks like maybe that bowl is shallower? That would help remove the initial angular momentum from an off-center pour. I'm less clear about how they're getting that one to work with no-circulation though.