They can play two main roles. The first is that of mediator and liaison with the police. Someone with some experience in handling police may be able to be assertive enough to handle typical police tactics and yet be someone with whom the police can liaise. This will help minimize the possibility of police over-reaction or violence. The other role is in collecting information that may be relevant to defence of people charged during an action.
Legal organisation becomes particularly important where mass arrests are being planned.
Issues are often given importance in the political sphere relative to the number of arrests that have been made. If this is the case then the deliberate policy of arrests may be successful as part of an overall lobbying strategy. In such a situation any organising or coordinating body should consider its policy in relation to criminal charges. As the title suggests this to some extent represents a betrayal of those willing to be arrested. In organising an action in which people will be arrested the organising body does take on some responsibility.