Can I give you a very short story from 'the other side', for context?
When I was 12, I travelled to Canada with my Guide company for International Camp. It was an AMAZING experience, we fundraised for a year to go, and I was really excited.
On our first day out in Toronto, I was in a group with the 'class clown', who, while not a 'bad' kid, was always testing the rules etc. We weren't friends per se (I was quite a quiet, introverted child), but we got on well enough and I thought I'd try to make the best of it.
At one point, said CC nipped off while our leader wasn't looking, ran into a shop, and stole a handful of sweets. We followed her and were trying to convince her to replace the sweets when we were caught by the store's security. As we were in a group, we were all implicated.
As a result, we were all put on 'lockdown' and weren't allowed to take part in any group activities for the next two days, and, of course, our parents were told when we got home. I could have DIED of shame (fortunately, my parents believed me when I told them the truth, but it still hurt).
Look at it this way: your child may have some behavioural or emotional problems which nobody perhaps nobody is aware of ATM, and, if so, that's probably a journey that has to be undertaken in other time. Please don't take the risk of spoiling other children's or teachers' enjoyment.