He was not arrested, he was being detained. Here’s what a LEO wrote when asked the difference between detention and arrest from http://www.realpolice.net/forums/ask-cop-112/81879-detained-vs-arrested.html:
Detentions are shorter in duration and scope than arrest, and require a lower burden of proof.
If I have Reasonable Suspicion that a crime has or is about to occur, and reasonably believe that a person may have information about this, I can detain them for a short period of time to investigate the matter. As part of my investigation, I can conduct a pat down for weapons (if I reasonably believe that they may be present) and seek information to determine exactly what is, has, or will happen. The timeframe can vary a bit due to each set of circumstances, but 20 minutes or so has been ruled to be a reasonable timeframe for detaining someone.
If I have Probable Cause to believe a specific person has committed a crime, I can arrest that person. At that point, I can conduct a complete search of their person for weapons, evidence, and contraband, as well as their vehcile if they are or have been near it recently. I can remove them from the scene and hold them (in jail) for 24 hours or until I get a warrant issued for the charges.
If anyone resists an arrest or detention, I am authorized to use force to apprehend them (in addition, resisting an arrest or detention is a crime, so resisting immediately gives me probable cause to make an arrest).
Normally I don’t have to use any “meaningful” physical force to restrain someone I am detaining or arresting. Most people cooperate on their own.
A person can usually tell (with me) because I’ll tell them when they are under arrest. If a case arises when I handcuff someone who is merely detained, I will tell them, “You’re not under arrest at this time; you are being detained while I investigate what’s going on.”
After 20 minutes, arrest me, cite me, or let me go.
Or else I get your badge and a check.
>If I have Reasonable Suspicion that a crime has or is about to occur,<
But in this case there’s some dork with a couple of little anklebiters he’s neglected to leash.
Come on, if that’s what you or your fellow officers consider a “crime”, we’re in a heap o’ trouble. The citizen complied with the leash rule once he was informed of the requirement. The ranger admitted she was there to educate. “Education” does not usually entail tasers in a free society.