Ministry = Relationship
I'm in the middle of summer camp season. Some of the camps directors wrote letters to go over schedules and expectations. Two of them explicitly said that I was expected to mingle with the kids outside of my performances. I was somewhat surprised by this, as I would have expected that to go without saying. Apparently that is not the case. I'm guessing that these camps have had problems with previous speakers who just wanted to do their performance and not have any interaction beyond that.
Honestly, it would never have even occurred to me that was an option. I believe the heart of ministry is relationship, and the deeper the relationship, the deeper the ministry. This is the model that the New Testament shows Jesus using. He didn't just preach to the "sinners." He ate with them, drank with them, spent time with them. Jesus didn't just shout up the tree to Zacceaus that he needed to repent. He spent time with him--began a relationship with him--and Zacceaus life was changed.
Yes, ministry can happen based on the rather superficial relationship that exists between a performer and an audience, but there can be so much more if the kids know the performer really cares about them. To a kid, love means spending time with them on their level. It's eating together, having fooz-ball battles and water-gun wars. Even when I'm just doing a single performance, I feel that some of the most important ministry time is when I mingle with people before or after the performance.
I'm certainly not advocating going to the other extreme of just showing love but never actually telling them about the source of that love. I'm also not talking about building a relationship to use as leverage to get people to respond to God. That would be manipulation, and would be wrong.
People need to be given the facts about God so they can decide for themselves how to live their lives. They're more likely to listen and seriously consider it when it comes from someone who has demonstrated love for them as they are.