China: Protesters Arrested for Human Rights Banner at Anti-Japan Rally · Global Voices
Oiwan Lam

More and more believe that the weekend anti-Japan protests in more than 80 cities are state sponsored. The arrest of three protesters in Shenzhen who were peacefully demonstrating in the middle of thousands of anti-Japanese protesters yesterday demonstrates how the police officers were effectively and selectively controlling and managing the protests.
According to citizen rights NGO news website, canyu.org [zh], three human rights activists were arrested in September 16, 2012, during the anti-Japan protest:
（参与2012年9月16日讯）今天上午，反日游行在深圳繁华街道华强北、市民中心等许多地方如火如荼进行，深圳民主人士姜卫东、子元等人按耐不住追求自由、民主、人权和平等的急迫心情，也跟着游行队伍打出自由、民主、人权、宪政等横幅，结果被便衣国保发现，于中午一点左右被抓捕，至今仍无任何消息，电话一直打不通。
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(Canyu's news brief on 16 September 2012) This morning, the grand anti-Japan rally took place in the Shenzhen downtown area, around Huaqiang North and Citizen Center. Shenzhen democrats such as Jiang Weidong, Ziyuan, took the chance to express their aspiration for freedom, democracy and human rights. They joined the rally, holding a banner with words: Freedom, Democracy, Human Rights and Constitutional Rule. They were discovered by undercover security police and arrested at around 1 p.m. They have been out of contact since then. Their phones are disconnected.
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Three Shenzhen citizen rights activists are protesting for democracy in the anti-Japan rally. They were quickly arrested by undercover police. Photos from canyu.com
The above piece of information somehow echoes with C Custer's observations about the police's role in the anti-Japan protest:
Like many people around the world, I’ve spent some of the past few days looking at photos and reports about the escalating anti-Japan protests in China. There is an excellent collection of them here for those that are interested… for anyone who has been to a protest in China before, your second inclination is going to be to say this: where are all the fucking cops?…
Now, let’s compare that to photos from the Beijing “Jasmine revolution” protest, an incident so small that it not only didn’t have any car-flipping, burning, or rioting, it didn’t even have any protesters. There was an army of police there…
[…] The evidence that China is turning a blind eye to these protests is overwhelming. The absence of China’s police forces is glaringly obvious, especially in contrast to the vast numbers that turn up and start jumping in front of lenses and smashing cameras whenever a protest China’s government doesn’t like is scheduled to take place. China has clearly shown it is more than capable of keeping anti-Japan protests under control if it wants to. The obvious conclusion now — the only conclusion now — is that it doesn’t want to.