I went in high school numerous times with the marching band, so I was pretty much alone there with my friends. My parents and siblings did come to every band trip, but we didn't necessarily spend every waking moment with one another. We would meet up for at least one day out of the entire trip or to eat a couple of times, but for the most part, we did things by ourselves. My friends and I were 15 when the band went for the first time when we were in high school, we were freshman.
There were also chaperones on the trip, but their only responsibilities basically included collecting our room keys in the morning and giving them back at night, that way they made sure we were back by the curfew, which was typically around midnight. The rest of the day we didn't see them and were free to go off.