Almost 2000 people were arrested in New York City during the various protests against the Republican National Convention, and many of them were arrested without warning (police are supposed to tell you to disperse or you will be arrested, rather than simply start arresting people, most of whom were simply standing on the sidewalk, sometimes not even interested in or participating in the protests) simply for being there and not breaking any laws. There were apparently preemptive arrest policies. It was sufficiently bad that a judge ordered the city to start releasing people due to the violations of their rights; he and many critics charge that the police were intentionally trying to hold people until the Convention finished.

Nets were used to separate and catch people indiscriminately. Reporters were even arrested. Once arrested, many were taken to Pier 57 (a makeshift jail facility made by putting a wire fence around some abandoned waste dump warehouse area) and held without access to lawyers or phone calls, typically for dozens of hours, in some cases for three days. There were various toxic chemicals there including waste oil and asbestos, and many people developed rashes and blisters and burning from confinement in Pier 57. Many people suffered wrist injuries from the plastic handcuffs which were placed on too tightly. Various other abuses occurred as well, e.g. parked locked bicycles were confiscated by police simply because they had been ridden by protesters. Many released prisoners did not get their cameras back. (For comparison, during the famous protests at the 1968 Democratic National Convention in Chicago, fewer than 600 people were arrested.)

Standing on a sidewalk at a political rally should not get you thrown into a jail for days with toxic chemicals and no access to a lawyer or phone calls, at least not in a supposedly free country.

http://nyc.indymedia.org/ has lots of updates
motherjones.com (account by arrested reporter)
thismodernworld account, parts one and two
newstandardnews.net
newsday.com

Preskaŭ 2000 protestantoj arestiĝis kaj ofte tre mistraktiĝis dum la novjorkaj manifestacioj kontraŭ la respublikana nacia kunveno. Ili arestiĝis senaverte, kaj multaj homoj, kiuj eĉ ne protestis, ekzemple raportistoj, arestiĝis, kaj ne povis uzi telefonon nek kontakti advokaton dum kelkaj tagoj. Multaj homoj vundiĝis pro katenoj, aŭ malsaniĝis pro danĝeraj ĥemiaĵoj kiuj bruligis la haŭton en la malliberejo (Pier 57) kiu ne taŭgas por teni multajn homojn longatempe. Ankaŭ vidu noticeton de mi ĉe ĝangalo.