Eh, the whole jump randomizer thing is too arbitrary feeling for me, but the gravitic field exit jump mechanic makes perfect sense as a prevention for catastrophic fusion, even a small ship would have it's own 100D 'bubble'.
Wait a minute. Does that mean ships can prevent safe jumps or cause misjumps just by impinging on the jumping ship with it's 100D gravity field?
Per T5, only if larger. Note that smaller ships inside the 100D limit don't cause the jumping ship an issue, but they do take a bit of a shock. (inside 10 diameters, they're pretty catastrophically damaged.)
At least we got Marc to drop (I think) that all a BB needs to do to drop a ship out is cross its jumpline while it's in jump. I pointed out that it would pretty much preclude small ship trade...