I'm pretty sure the LBB rule is simply to try to make the jump less than a death sentence, even though that's spelled out pretty clearly in the JTAS 24. It should be treated more like the cold start equation from ST:TOS "The Naked Time".
No pilot would willing risk their ship within the 100D.
A scenario I can think of is the PCs are being chased by somebody intent on destroying them and they don't have time to get to 100D before they are on top of them, so they press the Jump button and hope for the best. So if the enemy is going to destroy them, then they might take that small change of a misjump not destroying them as their only hope of escape, and in fact on another thread I outlined this very same scenario. A bunch of space pirates take off from a planet and a bunch of patrol cruisers are bearing down on the, the corsair can't hope to beat two patrol cruisers and there is no time to reach the 100D limit, so they press the Jump button, and end up inside an undiscovered Dyson Sphere located about 1 parsecs away from Regina. No one knows it's there, it has a thermo signature but it's fairly diffuse, and no one in the Regina system had reason to train their telescopes on an empty patch of space, and they don't do much astronomy there anyway.
Regina being a Moon of a gas giant, there are multiple moons and the gas giant itself which make this place an unpromising place to do ground based astronomy due to the light pollution. No one suspected that a huge artifact existed 1 parsecs away, it wasn't in any trade routes and nobody had any reason to jump in that direction until the pirates did, and they made a huge discovery! The pirates, not wanting to be caught, did not tell anybody about this discovery, after they exited from the Dyson Sphere, they recorded its location on their ship's computer so they could jump back to it if need be, this would make the perfect hide out and pirate base.