I just got the dreaded email. It's my fault though. Until now I have always started by making the first charge on an account in the sum of $100-$200 and then slowly creeping up - even upto $1400 in one swipe eventually - and have never had issues. I was on my last account which had never been used yet and only had $1000 available for fee-free swiping, and I was a little impatient, so at 7:59 PM EST I charged $999.98 on one card, and by 9:00 PM I got the email.
I assume that means they will be blocking even tonight's deposit even though it was already an hour after 8PM by the time they sent the email because they don't usually actually transfer until the wee hours of the morning. Oh well