We discussed this this morning and his answer was "Well, if we're not sure throw it out to MN!" 
PFB who is 8 started a new school. Old school had very strict rules on snacks and the like. Fruit or veg was offered to the lower school and upper school just had a no snacks policy. he was never hungry at school so there was no issue.
Passed the little shop on the way to new school this morning, queue of kids buying crisps for their break. Cue "Can I have some crisps for break please? They're allowed in this school."
I had no money and said I would sort something out for him to take to school tomorrow. Didn't commit to what that would be.
I know a packet of crisps a day isn't going to kill him, but I think that's a lot of crisps in a week. I don't want him to stand out or feel left out though.
Do I
a) Send him in with fruit. I'm his parent after all and his diet is my responsibility and I don't want him eating junk in the middle of lessons.
b) Send him in with crisps, appreciate it won't kill him, he eats so much fruit anyway and is very active and realise it may be time to stop being all PFB.