Fun fact: if you haven't been mirandized your silence is admissable, but not your answer. https://en.wikipedia.org/wiki/Salinas_v._Texas

The correct answer is to plead the fifth if a cop says hello.
It would be great if our system was set up such that there were people responsible for public safety the way firefighters are and, also like firefighters, don't have the looming threat of crushing you with the weight of the law, but unlike firefighters don't need to be ready next to a lot of bulky specialized equipment to be effective.
But it's not, so....