Recreational modules like all of the ship based modules that mimic planetary buildings need to be in orbit of a colony. A colony in this case is any bit of ground that you have designated as a colony. It could be a chunk of asteroid, a moon, a comet, or a planet.
When they first came out there was a glitch in that the ship a recreational module was on did not get the benifit of the module. Essentially you needed two ships together for all ships involved to get the benifit. I think this was changed with the last update, or is supposed to be changed for the next update.
To answer your question about putting them with a jump point defense force. It would not work as there would be no colony available to activate them unless you were incredibly lucky and had an asteroid close enough.
Brian