There is a difference between being arrested and detained. Being detained is not a big deal. You just go down to the station and they ask you questions (which, if you are smart, you will politely refuse to answer until you have consulted with an attorney).

Being arrested is a far more serious action. It requires evidence of a crime and the issuance of an arrest warrant. You can't get arrested on a whim, by the time you are arrested, a case has already been built against you and there is already evidence that you committed some crime.

It's very likely that what you described as "arrested" was actually "detained". Either that, or there is more to this story that you have failed to mention (such as, the person who called the police was (or claimed to be) a victim of the person who was arrested).

In any case, I'd love to find more information on this case. If you could find out who this person was, the name of the program he was on, or even better a link to the story...that would be great.