If you are unexpectedly arrested it's a good idea to make sure someone knows your name so you don't fall through the cracks. Try to get a witness to call into the movement legal hotline. Also call in yourself the first chance you get. This will prevent you from falling through the cracks. If you are released call again.
Some demonstrators decide to go limp when being arrested.
The intent in this is to slow the cops down, avoid compliance with the system, and avoid charges of actively resisting arrest. The technique has been particularly popular in instances of civil disobedience where demonstrators deliberately risk arrest in order to draw attention to something particularly irksome. This is a personal choice. Going limp can cause the cops to add charges of resisting arrest. Occasionally the cops use excessive force with little or no provocation.