peach rings

I'm confused about how discipline/management of student energy should be happening at my placement. A few weeks ago, Mariah, the programming director, briefly told us that Wordsmiths uses a point system. Today, she handed out printouts to each of the kids when they came in - Erica got 75% positive points yesterday, so the circle showed up 75% green. Another student only had 42% positive points. 

However, to my knowledge, none of the tutors have learned about this system or how to implement it. I didn't even know some of the rules until today (kids aren't allowed to go upstairs without an adult, students have to ask for permission to go outside, we don't use the "shut up" phrase, we don't use cuss words, no food from outside of Wordsmiths - especially candy). 

So I was outside with some of the kids for recess and I saw Bianca was talking with a friend. A few minutes later, I noticed that she was chewing something. Typically, the students are not supposed to have snacks of any kind until after recess when they go back inside (Wordsmiths provides fruit and yogurt). I asked her what she was eating. She said, "Nothing!" and backed away from me. She put one hand behind her back. Erica told her she better finish it quick. 

I asked her, "Are you eating candy?" Again, she avoided me and moved away. I could see 2 peach rings in her hand, in addition to the one already in her mouth. I repeated the rule - "You know you're not supposed to have any food from outside of Wordsmiths." She moved further away from me, and stuffed the other two peach rings in her mouth, then ran inside. "Aw, you're gonna choke on that!" Erica said, laughing. 

In the future, I think I plan on asking Mariah to explain the rules more thoroughly as well as the point system. I'll also ask Bianca, "How many points will those peach rings cost you?"

But still, I'm just - not sure of how to act in this situation. I've never had to parent my siblings (my younger brother is only 2 years younger, so I didn't really have to keep him in line much). So what do I do? Do I physically take the candy away or verbally reprimand? If she refuses, does that mean I should be forcibly take the candy from her?