Using Scrum of Scrum (SoS) as an early warning system

Typically we use Scrum of Scrum (SoS) as a platform to address issues between teams on a multi-team agile projects. Mike Cohen has a good post on the basics of SoS. SoS (as the acronym aptly captures this intent) is a good way to synchronize teams and resolve issues as they arise. However, it is a reactive approach. A better approach would be to turn SoS into an early warning platform so that teams can be proactive about imminent issues and prevent them from becoming real issues. In the process save everyone "valuable" times, and probably frustrations.

With that intent in mind, I suggested the teams of a distributed Agile project that I'm coaching now to use these questions:
                         1.  Is anything slowing my team down or getting in my team's way?
                         2. Is my team about to put something in another team’s way (DB changes, interface changes, UI changes etc.)?
                         3. What stories or bugs have been completed by my team since we last met?

Question 2 primarily, and question 3 to some extent serve as the sources of early warning. However, I quickly realized that teams would not knowingly report that they are putting anything that would impede other teams. So, I changed the question to be more explicit about the intent:

                  2. Is my team going to make changes to any shared resources (DB changes, interface changes, UI changes etc.), or checking in significant codes by the end of today?

This seemed to have helped. The Scrum Masters now need to listen in their daily scrum meeting more carefully to understand and be able to answer questions 2 and 3. Additionally, the teams are also tracking any inter-team requests at the SoS meetings.

How do you use SoS on your project?