I was studying SCM/Bug tracker integration when I found that it is not only possible to close and modify issues from the commit log, but it is also possible to create them.
But since the commit log is for code changes, I don't see why anyone would modify the code to create an issue. Please cite one scenario where this is justifiable.
One scenario might be where you're committing the fix for a particular issue, but you know the issue you've resolved is a short term fix for the problem.
In this case it might be necessary to open another issue in light of the short term fix so that you know you need to provide a long term fix somewhere down the road.
Maybe in a situation where a bug-report includes several "sub-bugs" : the commit can solve one of those "sub-bugs", and create another report for the remaining "sub-bugs" ?
Or sometimes, if you commit some hacky patch to quickly solve an urgent bug, you might want to create another report to "correct the hacky patch", to create a long-term solution ?