Now this is a question that is in the spirit of the article. IMHO it really depends on the circumstances in which the child was killed. If it was accidental, than Matthews actions would be a kind of penance. In God's eyes my understanding is that he would be forgiven. The OJ Simpson Jury would also surely set him free.
Of course, the point is moot given Matthews time-travelling powers. He could simply go back to a point before he killed the child and alter events.
I was considering it more as a purchased indulgence. I think I'm bound to amuse myself for the next day or so envisioning Dave Mattews showing up at and influencing key dates in history.