A police officer may not arrest any person for any legally protected health activity within this state as defined in section 570.17 of this chapter. 3-b. In the case of a warrantless arrest, the person doing the arresting doesn't have a warrant.When can law enforcement arrest me without a warrant? Maryland law permits sworn police officers to make warrantless arrests for criminal violations under the following circumstances: 1. A quick definition of arrest without a warrant: Arrest without a warrant means taking someone into custody without a written order from a judge. There are two ways that a police officer can make an arrest. First, in some cases, the officer can arrest without a warrant based on probable cause. (1) Offense in Presence of Officer. Remember, an arrest warrant requires only probable cause. It does not mean that you are guilty.