I always scratch my head about how people will go after the flimsy plot devices in less popular movies (or the more recent films) and not point out stuff like this in TVH.
Even worse than leaving stuff behind was the fact that they took a woman out of her time and brought her forward into the 23rd century. Imagine the ripple-effects THAT would have on the fabric of the universe.
You've heard of cowboy diplomacy? This is cowboy time travel. Kirk and company were the original Space Cowboys.