martok was second next to gowron, he had at least SOME influence in the decision, if not a lot.
And the Klingons did not close their borders in BoBW. They organized a fleet for support against the borg, although it was a bit too late (referring to wolf 359). According to Admiral Hansen in the 2nd part of the episode: "The Klingons are sending warships. Hell, we've even thought of opening talks with the Romulans."