ESD gets built up between human and earth. This device will either have its own local "ground" (isolated from the human body) or use the human body as its ground. Even if the potential between the human and earth is lots of kV, there wont be any problem, as no damaging current will flow between the electronics and the human. But it will need sufficient isolation between the electronics and earth (and maybe human) not to spark when bracelet gets between the human and a metallic earth surface.
This bracelet be programmed to do interesting artistic stuff when attached to a dancer :)
Wow!! New trends being set in fashion...and wearable electronics takes part there!! While pondering over wearable electronics circuit, a question occurred to me: how do we have a "real ground" for the circuit? How do we protect the circuit from the Electrostatic Voltage that gets generated in the body? Never thought about it.