Yeah, that is just a leash to keep him from running off. The dog's ok. But I am jealous that he salsas better than I do after I paid for lessons! Heehee
NO. He's NOT being held up and there's nothing cruel going on. What looks like a string is an illusion caused by the angle of the camera to the leash behind him. It's attached to the chair and he's leaning away from it to stay up. Jump to 1:30 in the video. He seems pretty happy there at the end.
I saw the string/rope too but if you wait until the end of the clip you'll see that he's just tied to the bottom of the chair and when he stands up he's pulled a bit by it - but he's doing it to himself and it doesn't look dangerous. I imagine he's just trying to get away from the leash and thinks trying to walk away from it is a good idea :P
I agree, this dog is clearly being held up by the collar with a string! At first I thought it was hilarious & adorable, but now that I see the string, it's just kind of appalling.