As a Canadian, I'm like:
You guys are getting food?
(School cafeterias with food service beyond selling terrible premade sandwiches for people who forgot their lunch are rare below college level and AFAIK what few exist all operate like a fast-food restaurant, where everyone pays for their meal then and there.)
It saves an amount of money so minuscule it literally makes no difference.
As for thickness, the iPhone 15 is 7.8 mm thick. You cannot in good faith believe that a 3.5 mm headphone jack can't fit in it.