Just because you have the right to remain silent doesn't mean the police have an obligation to let you know it. This might surprise some readers. The recitation of the Miranda warning every time TV and movie cops slap handcuffs on a suspect is so common that it might be easy to think that it's a requirement.
The Miranda warnings have become well known over the past five decades. You might even be able to recite them after watching Law & Order, Blue Bloods, the Good Wife or another law-related sitcom. These warnings were designed to limit the number of false or coerced confessions.