All the written descriptions of MST that I have read do say that they are services to get everyone on the same page and help the parent regain control and the difficult child to take responsibility. However, we did try it and the reality was much different. I'm sure it depends a lot on the therapist assigned to your case, but in our situation, the MST guy didn't want to hear about difficult child's history, didn't care about the real problems that we were dealing with, didn't want difficult child to see any other therapist (this is part of MST protocol), and only wanted to set up a behavior contract which was baseed on negotiation between me and difficult child. It really appeared that it was a bargain that if I would cook more meals that difficult child liked, difficult child would stay out of legal trouble and follow the rules. It had been court ordered for us, basd on a recommendation from a GAL who didn't know squat and made way too many assumptions about things. I had my son evaluation'd somewhere by an expert on childhood problems, took her written recommendations to the court and had the order for MST services removed so we could pursue the recommendations by mental health experts.
Also, with the mst person assigned to us, my son did not respect me or my rules more by seeing someone overule me. It only served to send my son a message that others could step in and I was not really in authority.
