Actually there is. While ZT at least tries to pay back the funds, the overall impression from mlawrence (and a few others) is that he tries to prevent exactly this from happening. Now the only one in the world that does not like a payback to happen is the actually thief himself, so...
... that's why ZT has only returned 15k of the 40k bitcoins he has stolen?
Chen exists no where except in Zhou's mind.
Right now only Zhou knows for sure, if Chen really exists, so your knowledge would prove that you are Zhou 