A common misconception is that police have to read you the Miranda warning before they arrest you or ask you any questions. This is only partially true.
First, Miranda warnings are not a right. You have a constitutional right against self incrimination (5th Amendment). Miranda warnings make you aware of those rights.
Second, Miranda warnings apply to “custodial interrogation”. This means you are in custody and you are being asked questions. This isn’t a straight forward concept. The simple explanation is that custodial interrogation means you are in the police station and the police are interrogating you. However, the concept is not that straight forward. Factually it is sometimes difficult to determine when an encounter turns into a detention…turns into you are not free to leave…turns into they are asking you questions that will sink you later on.
In fact, police are allowed to ask you questions during the course of an initial investigation during which you may incriminate yourself. But it may be a little different if you are handcuffed sitting on a curb and they are asking you those questions.
Police can walk up to anyone on the street and ask them questions. They don’t need a reason and they don’t need to Mirandize them.
Furthermore, Miranda warnings apply to testimonial statements under normal circumstances. For example, a sample of your breath or the color of your hair is not testimonial. Your consent to search is also not testimonial.
Additionally, although evidence obtained in violation of your 5th Amendment right to remain silent is inadmissible as fruit of the poisonous tree, the evidence may still be admissible under odd exceptions like the inevitable discovery rule.
A short blog post is a tough place to fully analyze this issue, especially since each case is a fact sensitive determination. If you have questions regarding this issue, please feel free to ask.