I think Koenma wouldn't take much pleading. He's not heartless. Plus I think Botan would give Koenma enough shit to make him do it either way. Koenma and Kurama seem to respect one another and when Shiori is taken away, it'll be a big blow for the plot and relationships. Kurama trusted Koenma but the guards were no match for Goshikuru, dun dun dun.