You should not tolerate headless horseman negotiating. Since this technique is so common in China, you should confirm in writing in Chinese before you send anyone to China that your Chinese counter-party’s team will be authorized to make all contract decisions. If the Chinese side will not commit to this, you should either send your own team to China that also does not have authority to make binding decisions or you can walk away. If the Chinese side agrees to using a team with full authority and then changes the rules during the in-person negotiation, you should terminate the negotiation and take the next flight out.