For damage control, you can apply a thin coat of clear nail polish to the tips of the crack. That will prevent it from propogating further. You only need to coat the tips, and not the whole crack, but I tend to coat the whole crack anyway, just for peace of mind. I carry a bottle in my glove compartment just for that - it was hard to explain a few times...

Just make sure you use clear... bright red would be more annoying than the crack itself