I'm reading the Plasma paper published a couple months ago, and on page 27, they talk about "Adversarial Mass Withdrawals" in the event of block withholding.
My question is, what if someone is offline during a mass withdrawal? The paper says in the event of block withholding "one simply should exit from this Plasma chain to another as quickly as possible." There's a fairly long process to do a mass withdrawal, but if someone is offline, I'm guessing they can't participate in time, so how is this problem solved?