Uhh, it's not hers just because she's a kid? Did it ever cross these idiots minds that she could have a father who bought it and just wasn't there at the time? They just jumped straight to "he's stole it"?
Sure you can argue that they've been watching her and know that she doesn't have a father. But that kind of argument is weak because she just bought the tent the other day and they would know of the captain and vice captain if they've really been watching her. In this case, they just saw an easy victim and went through with it. Ai-chan hopes their punishments are very harsh. If even a kid can afford to buy such tent with her own money, why is a party of adults unable to buy it and has to steal from a kid? It's like they're slum ruffians who steal money from kids they forced to sell drugs.