Do I have to wait until 4:00 PM to see what messages have been quarantined for me today?

You can see your quarantined email at any time either by logging on to your Web Console or by clicking the Request Summary Digest link in a previous End User Digest. Note that the Summary Digest will be a full listing of the messages in your personal Quarantine sorted by date with the newest ones at the top.

See also: Spam Filtering