The school my son goes to has a "zipline". Arrival is a 15 minute window. You pull up and a teacher comes to your car. You have to unclip your child though and have him ready to go (hard to do while you're driving up the driveway, but that's another grumble for another time...). It is recommended that you do this, but not required. Mainly a safety thing.
However, if you choose to bring your child in, you are greeted in the lobby by a teacher. You are not allowed to walk your child down the hall into the classroom. You pick your kid up in the lobby at the end of the day...again, not at the classroom.
The school he goes to is fairly dogmatic at least in other Montessori principles too.