If they don't get to the light in time they'll starve to death. But as usual there are always exceptions and some make it through. I wouldn't try to disturb it too much. If they do come through just rip them out.
I myself put down a mulch this spring, but not nearly thick enough, so I have teeny tiny seedlings of whatever shooting up on a daily basis. I just use my fingers as a rake and they're uprooted to dry out in the sun.
