Yeah - track them down, sure, but then call the cops.

Otherwise the crooks will realise they can just use the iphone as bait to also grab your wallets and macbooks.

Sounds like a startup opportunity: provide a service to track down stolen phones and return them to their owners.

Sounds like a pitch for a reality TV show.

You're gonna have to pay me more than $200 to risk a possible stabbing to retrieve your iPhone, in which case you should probably just go buy a new one.

Bring a gun, but in this case they had three guys and no reason to believe the thief was a violent criminal.