If the only goal is to provide an outlet for gambling, the slot machines could be programmed without a house edge, so that over the long term, the player gains

If the only goal is to provide an outlet for gambling, the slot machines could be programmed without a house edge, so that over the long term, the player gains as much money as he loses. But then soldiers might develop a gambling addiction which with those machines is harmless but would become problematic once they return to civilian life and rigged slot machines.