Vanishing items hack or glitch?

I've heard a couple of variations on this theme. In some, the character in question is playing normally and suddenly gets disconnected. When they log back in, some item they were wearing is gone. Others don't state whether they got booted or logged out normally, but also the items that disappear were equipped at the time.

So, to guard against this, perhaps you could un-equip any awesome items it would hurt to lose?