Look at it from the little snakes' perspective. The only time something is going to be rummaging around the hatching eggs will be when a predator has found it, and probably gobbled down it's siblings. So more than likely, instinct will tell the snake to get the heck out of Dodge while it still can! Surviving the possibility of a snagged umbilicus is much more likely than surviving being eaten.
When the eggs in a clutch begin to hatch, I try to leave them alone as long as possible. There may be a few late ones, but I try not to disturb them, yet remove the spend shells so they don't cause a bug problem to begin to crop up in the container.
In many cases, if you have a later hatching snake looking at you nervously from the egg, I have found just touching it on the nose will cause it to back up into the egg completely, and then I can go about my business and be done before it gets inquisitive enough to take another peek at what is going on.
Heck, this doesn't belong here, but let me get it down in print while I am thinking about it:
For years, I used to pull the fresh hatchlings from the incubating container, which contained vermiculite, and put them into another container containing dampened paper towels. I just thought this would be best for them. But I had a heck of a time with the paper towels getting mouldy or drying out too quickly, and some of the babies had trouble shedding that first skin. Getting a baby to dry out prematurely and being unable to shed that first skin successfully can sometimes be a serious problem for the snake.
Anyway, I noticed that when I would go out of town for the August Expo, and eggs were still hatching, invariably I would have a clutch or ten hatch out just before we left, and by the time we got back, they would have mostly shed their skins. I NEVER had any problems when they did it this way. Well DUH! So I just learned my lesson and kept them in the vermiculite, just putting in a water dish for them to get a drink when they wanted it. The problems vanished completely. When they wanted to be dry, they could do so. When they wanted to be in a more dampened environment, they just burrowed down into the vermiculite.
Sometimes all you need to do is to pay attention and you can figure out what to do to solve a problem.