Preschool "rules"

With this being N's first year in preschool, I don't know the rules of engagement so I always feel like a putz. There have been any number of occasions when I seem to have crossed some invisible preschool "etiquette" line.

Ex 1: One day while dropping N off, the mom in the car in front of me got out to help her son into the building with the snack box. There wasn't a car in front of her, so I pulled in front of her leaving plenty of space behind me for someone else to also be able to drop off. Although there were about 6 cars waiting, NO ONE moved, which left me wondering whether it is incorrect to "cut" in line for drop-off when someone is helping his/her kid in.

Ex 2: Awhile back, N had an upper respiratory thing--fever, running nose, stuffiness. She started ailing on a Wednesday, but was fever free by Friday. So on Monday I sent her to school. At pickup, her teacher tells me her nose was running alot that day. Was that her nice and subtle way of telling me to keep my kid home? Hell, if I wait for N to get rid of a runny nose (clear mucus, mind you), I would send her to school the first and last days and that would be it.

Ex 3: Every child periodically brings a snack to school. N gets to pick what she wants to take (although I push fruits and veggies). This time she opted for carrot sticks. Since I have never found individual single-serving baggies of carrot sticks, I put 4 carrots in each little plastic snack bag. When I picked N up, she said they had had carrot sticks, Goldfish and chocolate chip cookies for snack. Her teacher had made the cookies, but I wasn't sure if the Goldfish was because some kids hate carrot sticks or because I didn't put enough sticks in each bag?

I'm sure I'm making a deal out of something that is totally not, but I just feel like such a dweeb when it comes to a lot of this preschool parenting business.