If Gib played euchre it wouldn't pick up a bower. Here i have sympathy for Gib, you never gave Gib a chance to pattern out. 2N instead of 3N finds heart fit. Also, do you really want to play 3N if Gib doesn't have a ♦ stopper with a marked ♦ lead. But is true Gib has good 4-loser hand should be thinking slam.