Looks like quite a few people were taken down today; A's scheduled task script probably ran a scan.
Analyzing this, A's risk-control system seems to have two mechanisms.
One is a risk-control scan when you first register. If someone is taken down within a couple of days of signing up, it means the new user didn’t make it through the probationary period. During this time, the system mainly scans the environment, card information, and user information.
The other is a periodic scan. This scans historical conversations, the environment, and various other factors to calculate a combined score. If the score reaches the risk-control threshold, the account gets taken down outright.
A's really given me a huge National Day present. 
