Let me ask a serious question here.
If I'm at an event, let's say Nats or Worlds, and someone literally picks up my deck box and bolts for it. Would my running after him, and tackling him, or grabbing him, or some other way physically stopping him get me in trouble with Pokémon?
We're assuming I don't have time to report him, and he isn't going to let me talk to him. I witness him take my stuff and run. I take him down, subdue him and get my stuff back, or I let him get away.
Alternatively, he takes my stuff, I go talk to him, he says some profanity to me and walks away, am I in the right to take back my stuff?
Because obviously fighting is never the answer, and I'm not promoting fighting or violence but at the same time, if I walk away and tell a judge, "hey that guy took my stuff" how can I prove it? How can the judge in all honesty believe me over the other person. What’s to prove I'm not some guy trying to steal from another person by claiming something is mine. All the while he might just get away and I may never see him again.
Another situation, I yell thief, or somehow get a judge's attention as I bolt after him. Then take him down.
Because in all seriousness, if I watch someone steal from me, I won't walk away to report it while he gets away, and I'm sure as hell going to get my stuff back.
Also if he’s subdued, then he can then be handed over to the judges/security/official for them to deal with.
How would Pokémon rule this situation? Or would it be a very specific case-by-case basis? Food for thought.