What if you made preps like keys: They go away when you quit out.

(If preps on offline pfiles affect limits)
It would increase the # of preps available in the game.

It would increase circulation, decrease hoarding.

It would slow down relogging.
(It would mean someone who just logged on isn't immediately effective.
)
(It would mean people would reconsider logging out with an inventory full of preps)

It would mean people would stash preps places like clan pits, and that newbs would have some access to them.