Two comments on this.
1. Communication with the parents is absolutely essential. Any publication on youth ministry worth its salt will have this somewhere in its pages. However, do we really follow through? Do we take the time to make the calls, send the letters? Do we promptly return parent calls, emails, and letters? With the exception of when I have a day off or am traversing the globe on the latest harebrained-why-was-this-a-good-idea-pilgrimage/service-trip, I hold myself to a strict 24 hour max on any delay in returning communication. Even if I can't answer the question, I call back to say I don't know but I am working on the answer and will get back to you (I fill in a reasonable amount of time here). None of us like to be kept out of the loop, so why do we do that to parents?
2. Parental involvement. Dangerous words. Just about every youth minister can point to their train wreck moment when a parent volunteer caused massive amounts of damage to their ministry. I had the joy of my train wreck being all of four months into the job. However, I did not let this stop me from having parents involved in the ministry. I simply did a better job from that point on in vetting and preparing volunteers. Five years in, I'm still on a learning curve for this.
Side note - youth ministers, don't get caught up in your bubble of ministry, youth, and all that is church. Remember that wisdom can come from unlikely sources so keep your nose in non-church media.