I get this question all the time. Unfortunately, no. The police don't have to read you your rights unless they're going to question you and unless you're actually detained. If you are detained or in custody where you're not free to leave and they question you, they must read you your rights. If they don't read you your rights anything that you tell them about the case can be suppressed in court and it won't come out. If you confessed under those circumstances, that statement will not come in.