Hopefully it only sells pizza.
When I was at high school there was an ice cream van just outside the school gates every lunchtime and home time. It did a roaring trade.
As well as selling ice cream, drinks and snacks it also sold single cigarettes. 
Currently there's an ice cream van which parks on the road outside my grandchildren's primary school every Friday - it's every weekday from when the weather improves. Lots of parents complain about their children wanting an ice cream before their main meal and the children having huge meltdowns because they're told no. They want the ice cream man banned.
My grandchildren ask for ice cream every time they see the van. My granddaughter has been at that school for 5 years, she has autism and has always accepted 'no' for an answer (without meltdown) as do her younger brothers (also additional needs). I think that the van is allowed to trade where it wants and must be doing a good trade because it's been there for years. So it must be lucrative as it always seems to have a long queue of customers.
Everyone has the choice of what and when to eat. When children become more independent at high school they choose what they eat. It's better nowadays with parent pay where children are more or less forced to eat in the high school setting. When I was in high school I never bought dinner tickets. I used to go to the 'row of shops' nearby like a good proportion of others. I used to share an uncut loaf with a friend, hollow it out, fill with a bag of crisps and 'supplement' with a polystyrene cup of soup. Some days it was chips and beans if you managed to get a seat in the cafe. Some days it was a pie. Some days a can of coke and a mars bar.
But then I walked to and from high school - every day, in all weathers - took just over an hour. And I carried a tenor saxophone every day in a massive case - as well as books, PE kit, occasional baking equipment. It never entered my head that I could ask my parents for a lift because we had school buses for that purpose which I decided I wouldn't be using.
It's down to individual responsibility.
But if I could ban something outside the school gates (literally tethered to the school gates) it would be dogs. Since Covid, children now have to wait outside the school grounds until two mins before the registers close (how on earth does that work?). So hundreds of parents and children have to stand either on the drive/road which goes into school or the village green. The village green, at drop off/pick up, contains at least a couple of dozen dogs (mainly reactive jumping animals) which parents insist have to clutter the school run. They foul the village green for the children to traipse animal excrement into school on their shoes, smash it into the class carpet and then sit on the carpet, leaning on their hands, picking at the soles of their shoes, playing with the hair of the girl in front of them, several times throughout the school day. It's unbelievable how often 'noro virus' goes round schools. Must be every week - amazing how many times the teachers insist that my grandchildren have noro virus - I had no idea you could catch it so frequently.
I had to pick up my grandson from that school today because he'd been asleep for two hours (he has epileptic seizures during the night and he is always tired and any focals or absences at school can make him sleepy afterwards). When I got to the school office they asked if I would wake him as they didn't want him to be confused on waking up and induce a seizure. When I got to the class he was lying on several cushions on the floor in the book corner. I bent down to wake him and had to exclaim 'oh no I can smell really strong dog dirt'. The class assistant brightly replied that she thought she'd cleaned it up. I ended up having to put an extremely whiffy child in my (new) car to take home with me and had to decontaminate his uniform (none on his shoes) just what he'd picked up from lying on the carpet/cushions. I hope he doesn't develop 'noro virus'.
H can take my car to be valeted whenever, I'll use my other car in the meantime. It only has two seats - who will do the school run now?