Not really, if you get a bad placement roll just do not come through. Nothing forces you too, and an open jump point is often as useful for forcing manuever and force splitting as a ship sitting in a bad place.
That's the core of the debate with the JP affects from a balance standpoint, you do not have to use the point created. Most of the time when we've looked at using this tactic jp's are used to destroy the low hulled scouts on the edge of a formation with one usefully placed point that all the ships actually emerge from.
To the new guy - this is a really potent tactic. JP's in the rear of the enemy will often force him to consider turning signifcant force away from the original plan just to cover against one potential big ship in his rear. Opening the jump points can give you utterly safe initiative sinks for the first three turns of the game, as you can open, and then hold open, the points only coming in once the big ships have engaged. Good use of Hermes if your an earth player, they can stay out of the scrum while lobbing missles at choice targets.
Ripple