Gillian - I just saw what you were referring to about MatchBot initiating a merge! At the bottom of a profile, in the merge section, it's the link for the creating a pending option ([initiate a merge]). I never noticed that before.
And I just completed a merge that MatchBot had proposed for someone in my tree last night (before my computer crashed). When I restored my browsing session, that match had the message:
A proposal to merge Sarah Noland and Saryah Noland was approved by MatchBot WikiTree and Sharon Winsatt. The merge was completed on Jun 23, 2016.
This also explains how some folks have gotten the impression that MatchBot is approving merges. In the "Browse Matches" list where I found the pair, it showed only that Sharon had approved the merge & that someone from the trusted list of the other profile needed to approve it (I was able to complete it because it had gotten the 30-day default approval).