Servant or Volunteer?

I'm still reading Mike Slaughter's Renegade Gospel.  He says this:

...we come to Jesus offering ourselves as volunteers rather than as servants.  ... Volunteers serve out of convenience of their calendars, controlling when, where and how they participate. ... Volunteers follow Jesus up to a point - the point of interference with their lifestyle.

I get what he is saying, but I don't completely agree with it.  Do you?

Slaughter doesn't call people volunteers in his church - he calls them servants.  I agree that we are to be servants of God - available and obedient to God's call, regardless of the inconvenience.  I don't believe (and maybe Slaughter doesn't either) that we are servants of our church.  God has placed particular calls on my life, and that includes the work I do in my job, in my family, in my community and in my church.  They are all calls from God, and there are times when one will have priority over another.  God calls me to know how to do that - and that is part of the service I am called to do.

I can't always say "yes" at church, because sometimes it's not the highest priority.  Another part of my service is higher.  Sometimes I have to say "no" to a family event because I have to do something for work.  Sometimes I need to take time off from work for a family responsibility.  Sometimes I miss church, work and family time to go on an Emmaus walk, and for that weekend, God has called me to place that at the highest priority for my time.

I asked a pastor once, "Why don't you like the Walk to Emmaus?"  His answer was that it pulls people out of worship.  I'm not convinced that this was actually his reason, but still - God calls us to many ministries, and calls us to prioritize them (with God's guidance).  That doesn't make me a flighty "volunteer."  It makes me a servant "volunteer."