Securing the forest boundary

In the article SID filter as security boundary between domains? (Part 7) - Trust account attack - from trusting to trusted , by Jonas Bülow Knudsen, Martin Sohn Christensen, Tobias Thorbjørn Munch Torp, they describe how the security boundary of the forest can be breached by an admin in the trusting forest and I will explain how you can mitigate this problem.