A lot of these protesters and "passerbys" are getting in trouble with the police, but I've been avoiding saying much because I haven't seen it myself and the administration has insisted they are not concerned about symbolism, but are merely preventing illegal demonstrations and making sure Chen Yunlin will be safe on his trip here.
But a friend of mine with some first hand info in Taipei just called me about an incident that occurred sometime close to Chen's lunch at the Ambassador hotel today (he was shouted at there; someone yelled "Taiwan, China, one side, one country!"), A music store near the hotel, was playing music so that pedestrians might be attracted to drop in (like all music stores do). It just happened to be playing The Song of Taiwan (台灣之歌). The police went into the store, telling them to change the song and shut the doors.
Between that and the detention of a documentary film maker who was visiting a friend at the Yuanshan Hotel (detained really for filming, but officially for refusing to produce an ID, apparently, although foreign tourists nearby were all taking pictures), I think it's fair to say the government really is going WAY too far. The excuse that police are only taking measures designed to protect Chen's safety and avoid illegal demonstrations is simply not true. Martial law really is in the air. Arbitrary detentions and "banned songs" are back from the dead.
The DPP will hold an illegal protest on the night they expect Ma to meet Chen (their permit was denied, but the DPP decided to go ahead anyway). We will see what happens next.