Conversation so far:
What happened with Ai Weiwei's tax case?
In June 2011, the Beijing Local Taxation Bureau demanded a total of over 12 million yuan (US$1.85 million) from Beijing Fa Ke Cultural Development Ltd. in unpaid taxes and fines
What did Ai Weiwei do?
According to Ai Weiwei's wife, Beijing Fa Ke Cultural Development Ltd. has hired two Beijing lawyers as defense attorneys.
Are there any other interesting aspects about the Ai Weiwei article?
Ai Weiwei's family stated that Ai is neither the chief executive nor the legal representative of the design company, which is registered in his wife's name.“
Was Ai Weiwei convicted on his tax case?
In June 2012, the court heard the tax appeal case. On 20 July, Ai Weiwei's tax appeal was rejected in court.
Did Ai Weiwei pay the fines on his tax case?
The court upheld the 2.4 million tax evasion fine. Ai Weiwei had previously deposited 1.33 million in order to appeal. Ai said he will not pay the remainder.

Question: Why did they do that?
Self-contained rewrite: Why did Ai Weiwei decide no to pay the remainder of the 2.4 million tax evasion fine?