ExpertNovice - I just wanted to point out that the suspected Silverlight issue did no have to do with it being installed on my computer but rather that a Silverlight upgrade had been performed on the site I was accessing.
That said, I'm no longer convinced that was the true (or only) cause. One would expect the Silverlight upgrade to produce the Anti-Exploit alert once, the first time the upgraded site was accessed. However, I continue to have intermittent occurrences of the Anit-Exploit alert. My network admin and I are now beginning to think it is a conflict with other security packages, namely System Center Endpoint Protection (SCEP) in our case. The Anti-Exploit alerts only occur when I'm running my automated tests (which access mostly internal intranet web sites) AND when a SCEP security scan is running at the same time. Yet it doesn't happen every time, so we're thinking it must also have to do with the timing of which local cache files are being accessed by SCEP and/or Internet Explorer, potentially causing a conflict and triggering the Anti-Exploit alert.
At any rate, the behavior is seemingly inconsistent, but we are confident there is no true exploit occurring and believe it is likely just a conflict between security products. Just wanted to mention that since you said you are evaluating MWB to see if it should be added to already-existing security layers.