I think they're somehow controlling the spin top right before it leaves the string when it is just right on top of the target! They can surely throw very precisely, but for some reason I doubt they could achieve what they did with just throwing (ex. land on a bottle cap, or inside a small rubber band). They have to be making corrections after the top leaves their hand somehow, especially when it flies near the target.
Here is a Taiwanese website that teaches how to target throw a top:
http://163.17.220.4/whipping-top/materials.htm One important thing they stress is that the string must be just as long as the distance between you and the target (you can see it in the video too). I presume that it makes it easier to control even after the top leaves your hand... They never specifically say anything about controlling the top after the toss though, so I don't know. Maybe the feeling comes with practice.
P.S. I'm planning to translate the entire site in the near future when/if I get the owner's permission
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