WHEN MUST THE POLICE ADVISE A PERSON OF THEIR RIGHTS - AND WHAT IS THE IMPACT IF THIS IS NOT DONE
Before law enforcement is required to advise a person of their rights (i.e. the right to remain silent, the right to consult a lawyer, etc.) two conditions must exist: (1) the person must be "in custody" (reasonably believe they are not free to go) and (2) they must be subject to interrogation (questions designed to elicit an incriminating response).
Many times an officer investigates a situation, to try to learn what occurred, and only after they get a person's story, do they arrest or detain the person (see additional blog explaining that people do not have to talk with the police). Whether a person is in custody or not free to go is subject to many different factors, and is decided case by case.
I often get asked if a case will be thrown out because a person is not advised of their rights. It takes looking into.
If a person should have been advised of their rights and law enforcement failed to do so, the remedy the Courts give, is to suppress the statement made by the person who should have been advised of their rights. The case does not get thrown out - it just removes that evidence from what the prosecutor can use to try to prove the case. If the only evidence of the crime is a statement from the persons own mouth - and that gets thrown out - does the case end up getting thrown out (since there is no evidence to use to try to prove the case).