A magistrate is a judicial officer who makes determinations regarding probable cause. For example, an arresting officer presents an arrestee to a magistrate and makes his accusation and gives his evidence. The magistrate makes a judicial determination as to whether probable cause or legal justification for the arrest exists.
Or, the cops present the probable cause for a search warrant to a magistrate, and the magistrate issues the search warrant if he agrees probable cause exists.
Basically, a magistrate is (supposedly) the judicial buffer between the executive branch and the citizen with regard to searches and seizures. I said supposedly because plenty of magistrates seem like rubber stamps for police.
Personally, I can't see any point in demanding to see a magistrate during a Terry Stop. All the magistrate can do is tell the cop there is no probable cause for an arrest and to let you go. But, there wouldn't be a Terry Stop if there was probable cause, anyway. The cop would just arrest you instead of detaining and questioning you.
And, the cop isn't going to take you to a magistrate without probable cause, anyway, now that I think about it. There are court cases that discuss whether presentation to a magistrate is the formal beginning of the legal process, as in whether its at that point the formal accusation is made. A cop isn't going to turn a Terry Stop into a false arrest by taking you to a magistrate even if you request going to the magistrate. Or, at least I wouldn't if I were a cop. And, the cop isn't going to let you drive yourself to the magistrate right in the middle of his Terry Stop.
But, lets say you did somehow talk the cop into taking you to the magistrate. Its not like you are going to start making sworn statements to the magistrate without your attorney, anymore than you're going to answer the cop's questions during the detention.
So, what's the magistrate going to do? Tell the cop to let you go because you're not giving probable cause? The same thing you'd accomplish by invoking the 5th Amendment and shutting up during the Terry Stop?
Also, magistrates don't make determinations about reasonable articulable suspicion (RAS). As far as I know, that determination is made during a pre-trial suppression hearing. At least, that's what Terry v Ohio says.
So, no. I can't see any point in asking to see a magistrate.
ETA: It might be fun to see how the system dysfunctions when you throw it a curve. "Officer, I would like this interview to occur in front of a magistrate." Of course, you might get a dummy of a magistrate who tells the cop, "Oh yeah? You saw him OCing and a citizen accused him of brandishing? Sounds like probable cause to me, officer. I'll approve your arrest." Then the cop is practically bullet proof against a false arrest lawsuit. Good faith. The magistrate told him probable cause existed.
Now that I think about it, there was a non-incident some years ago where some cops were called because of some OCers having dinner at a restaurant called Champs or something. Cops came. Didn't confront the OCers--just stood off to the side while trying to figure out what to do. One called a magistrate for guidance on the legality of OC. The magistrate was dead sure OC was illegal and all but ordered the cops to arrest the OCers. The cops didn't. Lucky for everybody involved, someone else, maybe a cop supervisor, cleared up for the cops that OC was legal. My point is, a mistaken magistrate may actually get you arrested.
