[tptacek]

Your first example is naive. The police cannot arrest you absent an actual crime, but they can detain you for a "reasonable" amount of time; if you simply walk away from an officer, you are in fact impeding an investigation. There is a clear difference between an arrest and being "detained": during an arrest, the police can search you and your vehicle, put you in restraints, and drive you away to a police station.

That there are subjective offenses you can be arrested for and that the police could abuse strikes me as a simple fact of life. You can also file complaints, (in most jurisdictions) record the abuse with your camera phone, and (in crazy cases) sue.

[pyre]

In my example, the people were 'detained' for a few hours, during which they were not asked any questions at all. They just had to sit around at the police station twiddling their thumbs. In my mind, this just police intimidation. Some police officer didn't like them or what they were doing, so they decided to harass them. I don't think that, as a society, we should just accept this as a fact of life. By doing so, we give the police carte blanche to continue doing so, and to attempt to push the envelope even further.