That was pretty irresponsible, and the original poster's response was certainly understandable, but I kinda feel like some people here are overreacting. I highly doubt they'll do it again, as they probably feel really terrible. I did that once when I was in high school. Our house was wide open all day. My parents just calmly said to try to remember to make sure it shut - and I did. No harm, no foul. No yelling, no reminding, no childish attempts to "teach me a lesson".
Doors sometimes bounce open when you think you've shut them. Like I said, I'm sure they feel guilty enough as it is. If I was them, and I had to hear about one mistake over and over from someone hosting me after a long day of corps, it wouldn't exactly make me want to change my behavior. They're DCI kids, so they probably wouldn't make the same mistake twice.