How do you know that Nefario is still even using his bitcointalk account?  How do you know someone did not hack his account?

Give him the excess coins after he returns your assets and sends an actual email out.  That would prove it is him.

Also, how do we know the database is even intact?  It took less than a thought to delist all of Goats assets and send him claim codes.  If Nefario can run the payment script twice he is just as likely to 'accidentally' delete the database.  You really want someone that flushed away 1,000 BTC in 10 minutes to play around with the database well more than 1,000BTC?

Why would he 'accidentally' erase the database?  People might be able to come after him for lost bitcoins, but they can't come after him for the assets, especially unregistered, unregulated assets denominated in something not considered money.  Nefario is the only one with the evidence.  This whole claims process should have been done by someone else at BitcoinGlobal since Nefario pisses his pants when he even imagines a government regulator.

He could have easily sent the assets back first, then the bitcoins.