I have same situation at DS school except I'm disabled and can't walk very far. I have a wheelchair but for various reasons can't get to the school in it, but can't drive and then get it out if the car either. It's too heavy without a hoist and the street is to slopey to use the hoist, it needs even ground.
So there is only space for around 5 cars to park safely. Then another 5 or so block driveways, the pavement (another reason I cannot rely on using my wheelchair) and in front of the gate itself.
If just one parent didn't park, and walked a bit further from a side street instead, it would be an enormous help to me. I can't walk, you can.
The upshot is that my 5 yr old gets kept back after school because I'm not there, and he asks me why. It breaks my heart to explain I was on time, I was waiting round the corner and had to wait for others to collect their kids first, move their cars (after long chit chat in the playground) and then move my car close enough to walk.
And in the morning if I can't get a space we have to sit and wait in a side street. DS cries if he's late, so always cries when he hears the bell and doesn't understand why we can't just drive over them like a tank. He's developing anxiety about time and lateness. School are not counting it as late, they understand but he does to. He knows he's late if he goes through the office door and is last in the classroom. This is not his fault.
Or I can park like a dick and join the rest of them, and sometimes I do. But only my car has been pictured and posted on the school Facebook page by other mums, abusing me. And my disability was known and mentioned. It Didn't stop them and their awful comments. I cry most days in the build up to the school run and start worrying about it on Sundays. I can't enjoy family time and this is having a very real impact on our lives. I'm trying very hard to work full time, support my family and raise my son. Being disabled on top is hard enough, this school run bollocks is making it near impossible to be actively involved in the school.
So if you can, walk. Please.