An abnormal spike coupled with Typed/Bookmarked referrals (i.e. direct
traffic) and also with unusually large bounce rate sounds suspiciously
like bot traffic. If these are bots, then they wouldn't normally save
any cookies, let alone Adobe's visitor ID cookie. As a result, every hit
is essentially a "new" visit. And since bots also normally don't send
any document.referrer data, AA would then classify them as
Typed/Bookmarked referrals.