From Beyond Relevance:
The intimidation factor for a lone visitor in a new church is simply huge.
But it is nowhere close to the stress and vulnerability that is put on a churchgoer who invites a visitor. All inviters put their reputations on the line every time they invite someone to church. You can rest assured that your church members will not invite someone if they do not expect a positive outcome. And most of the time, that's why one church isn't growing and the church around the corner is. It has led us to say that "People are not ashamed of Christ, they are ashamed of their church....
...If members walk out of your service saying, "I wish my unchurched friend had been here," they will start to think about inviting their friend. If a member walks out of your service three weeks in a row and says every time, "I wish my unchurched friend would have heard that," nothing will stop that member from dragging that friend through your doors."
The whole thing is well worth a read, including a 6 point checklist to help work out whether folks would feel happy inviting their friends.
Cartoon by Jon Birch at ASBO Jesus