One thing is for sure — the Saturn system is extremely complex. It is quite possible that different materials get separated in the plumes, so while the part that Cassini flew through lacked salt, the salt *was* present at other elevations. We know the plumes interact in surprisingly potent ways with Saturn’s magnetosphere — so much so that the old method of computing Saturn’s day (measuring radio pulses from the planet) doesn’t work! Enceladus puts significant drag onto Saturn’s magnetosphere, so much so that it rotates more slowly than the planet itself, artificially slowing the regular radio pulses that would normally be used to deduce the rotational speed of a gas giant.