The wood frame is secured by the string, but the string is being twisted. Shouldn't the cg of the glass/ frame combo be moving up/down due to the twist being imparted by the twisting/ untwisting string?
It would imply the cg of the entire assembly is in motion, causing it to want to tip. Unless the cg is moving up/ down exactly over the contact between the wrench and bottle. And that's more impressive.