I feel that intervention is something that should be taken on a case by case basis which is what makes it so difficult to enforce. I saw him steal from a very young person who was sitting there, first I told him to go deposit his silvers, then I proceeded to scold the lousy thief, if I can see ya you lousy. I intervined on a level that hurt nothing but his pride so I feel it is ok. Am I right? Depends on who you ask. I play someone who helps others in this sense I felt I was helping/protecting the littler adventurer.
As a side note didn't even know the one I was defending so it wasn't a situation like: Oh pick on my little character I will show you meet his big brother kind of crap because that is just weak.
I have a real young rogue I have stolen twice and been caught the second time so I am waiting till he is a bit older to try again. When I got caught my answer to what I was doing was this "I am sorry I am new in this town and I needed to get silvers to pay for my mothers potions she needs for her ailments. I would have asked but I hate rejection, here take your silvers plus what I have." I got to keep his silvers and walked away. Had I been killed, slept, blinded, etc I would have taken it I am responsible for my actions.
Bottom line case by case basis and how would your character handle it?
Anticor Rifling, Giantman Wizard reg