Over the years, many clients of ours have told us that they were not read their rights when the police officer(s) questioned them. They then want to know if they can get their statements "thrown out" or the whole case against them dismissed. Here are 2 important things I tell them that apply here. First, in order for the police to have to give you any Miranda rights (i.e. "you have the right to remain silent...."), you have to be in "custody." For example, if the cops simply knock on your door and ask to come in and ask you some questions (or approach you on the street to do the same), they DO NOT have to give you your Miranda rights. This is because you are not in what the law calls "custody" (in other words, you are free to go and/or close the door). If a police officer pulls over your car and comes up to your car window to ask you questions, you MIGHT be in custody and you MIGHT have to be read your Miranda rights if the police want to use what you say after that against you (these situations are very fact specific). If the police officer has placed you under arrest, you MUST be read your Miranda rights if the police want to use what you say after that against you. This "custody" aspect of the Miranda rights issue controls the outcomes of many cases. This very issue is in play right now in a rather big federal case here in Cleveland.
Second, a technical violation of the Miranda rights rule does not automatically invalidate the arrest or automatically require that the case be dismissed. It just subjects the post-arrest/custody statements made by a defendant to a motion to suppress - while most of the other evidence the police obtained (unless it was the result of what you said) remains in the case.
Advice: Anytime the police call or knock, ask for a lawyer. Always.