Being read your Miranda rights, or right to remain silent, is implicated at the time you are “under arrest.” There often is much confusion as to what “under arrest” means.
You are under arrest at the time you are in custody and a reasonable person would not feel free to leave. At the point you are under arrest, the officer must read you your Miranda rights, or right to remain silent, before questioning you. The failure of an officer to read you your Miranda rights might be a violation of the Constitution. However, the officer’s violation of your Miranda rights does not mean your case, necessarily, will be dismissed.
If a judge determines your right to remain silent was violated, the judge will suppress (or exclude and thus not allow the jury to hear) your statements after the violation (and in some instances possibly more statements). Notice that this is not the same thing as a case being dismissed. In some cases, even without statements, the prosecutor may decide to proceed with the case. Thus, a violation of your Miranda rights, or right to remain silent, does not necessarily mean the case will be dismissed. Your statements might be excluded, or suppressed, but that doesn’t automatically end the case.
The important thing to remember here is, whether an officer reads you your Miranda rights, or whether you’re even under arrest at all, very little good usually comes from talking to the police. It is best to remember, you have a right not to talk to the police and not to implicate yourself in a crime and avoiding either one should be avoided. Thus, the best advice…no good comes from talking to the police and the best response is, “I want to speak with my lawyer.”