As part of the arrest paperwork, police officers provide this notice in writing to the defendant. The statements are then litigated later on to determine if they were voluntarily made.
As part of our pro se series I'd like to introduce 710.30. These are statements defendants have actually made to police officers before or after arrest.
The police were called to a store for complaints of a person stealing. By the time the police arrived, the defendant had left. The store video crystalized his image forever, however.
With the video, the police were able to locate a suspect matching the person seen stealing in the store video.
They brought him back to the store and showed him the video. The questions that followed:
Defendant: (while watching video) That's not me.
Officer: Unless you've got a twin, that's you.
Defendant: I do got a twin.
Officer: (thinking he may have made a mistake) What's his name?
Officer: (believing he may indeed have the wrong person) What's his date of birth?
Defendant: I don't know that.
Officer: You're under arrest.
Officer: His date of birth is the same as yours.
Defendant: Oh yeah. Ya got me.