Thanks for the reflection, Aaron, I enjoyed reading it.
It did make me think about how the American church avoids action and therefore avoids "sinning boldly" as they act on their faith. Evangelism is one area that the everyday church-goer avoids action in, for sure, but I wouldn't say it's the major one. We actually have a lot of "evangelism" going on in terms of people saying that they believe in Jesus. But I would say it's an evangelism that doesn't direct people to the nature of who Jesus is. It seems that half of all the professional athletes now-a-days are quick to "give glory to Christ" when they have success on the field. What that message seems to be communicating is "I've attained the dream that so many people in our culture are longing for, and I have Jesus too! I've got the best of both worlds!"
Where I would say the American church doesn't know how to "sin boldly" (me included!) is to LOVE, with the love of Christ, people who are different from them. Our society is so divided and isolated racially and economically, and that isolation bleeds into the church. We are good at loving those within our churches (who look and act exactly like us), but we have no concept of extending God's love across those barriers.
One example that came to mind while I was reading your note was loving Latino immigrants. It is a tricky area because many are illegal, but God calls us to care for the sojourner in our midst. Not to mention the fact that they are here because of injustice and oppression back home. So, how do we love the immigrant in our midst? There aren't a ton of clear cut answers, and there will no doubt be sin involved as we try to do it--but we've got to "sin boldly" as we extend God's love to those who are in a very different situation than us!