You’re walking down the street. An officer approaches you, asks you how you’re doing, and casually requests to see your ID. Have you been detained?

In most places, the answer is no, because you’re entitled to ignore the officer and walk away. Because the officer hasn’t detained you, it’s likely that whatever he discovers through the interaction could be admissible against you in court. (If an officer detains you without reasonable suspicion, incriminating evidence she comes upon during the interaction will typically be inadmissible in court for most purposes—see What is the exclusionary rule?)

ID Request

In 1980 the U.S. Supreme court ruled on the case of a woman at an airport who appeared to fit a drug courier profile. The high court ruled that a detention didn’t occur when agents not wearing uniforms approached her, identified themselves, and requested her ID and ticket. (U.S. v. Mendenhall, 446 U.S. 544 (1980).) Most courts—but not all—to decide whether a request for identification constitutes a detention have likewise ruled that, by itself, it doesn’t.

When it comes to detention, the operative question is whether a reasonable person in the subject’s shoes would have felt free to leave the situation. In that regard, courts see a big difference between officers asking for and demanding identification.

(To read about other factors that go into a determination of whether someone has been detained, and to learn how state law complicates the matter, check out Uncuffed.)

Handed Over

Let’s assume you go ahead and hand your driver’s license over to that officer we earlier encountered. Surely, at the point the officer has your ID, you’re under detention. Right?

There may not be a clear-cut answer in this situation, at least in some jurisdictions. In one California case, for example, a man was in the passenger seat of an illegally parked car. An officer requested identification from him and asked whose car it was. The man handed over his identification card and gave a somewhat curious answer about the owner of the vehicle. The officer kept the ID while running a check on the car and its occupant, and while writing a parking ticket. An appeals court held that, at the point that the defendant handed over his ID, he had been detained because a reasonable person wouldn’t have felt free to leave. (People v. Castaneda, 35 Cal.App.4th 1222 (1995).)

But other California courts have held just the opposite, essentially saying that it makes no sense that a consensual encounter would turn into a detention when the citizen willingly relinquishes identification. (See People v. Leath, 217 Cal. App. 4th 344 (2013).)

The lesson is that whether you’ve been detained by a police officer depends not only on the circumstances, but also on the interpretation of law that your courts follow. An experienced criminal defense lawyer should be your go-to for reliable information and advice.