i reckon it has the potential to be abused, i don't know how, but I'm sure someone will find a way to do it.
here's probably one example (probably a bad one too) of what could happen,
One player runs up to a group of high leveled enemies, logs off, while another player lures the enemies away from that area, the other player then logs back on and can get past that area.
also, what information is saved when a user logs off?
will their hp, mp, spell delay or whatever else stats be reset when they log back on?
if this gets the go ahead, will the user be forced to respawn at their last location or will the have the option to respawn at a nearby inn?