I leave mine in the car, i now have three and i'm always on my own when filling up. The thought of having a baby in my arms and a 4 & 2 year old running around a petrol station makes me just as nervous about leaving them in the car. I keep the windows up because of the fumes unless it was a stinking hot day. Once i have filled up i grab my purse tell the kids i'll be straight back and lock the doors. I'm as quick as possible and i'm constantly looking out the window of the servo while i stand in line.