I found it interesting that they actually published the list of accounts: https://www.reddit.com/wiki/suspiciousaccounts
Looking through some of them, I would be interested to see a bit more detail into how they identified these accounts. Because, for example, this account[1] never seemed to post anything political at all, but is included in the list. 1: https://www.reddit.com/user/reggaebull
Elsewhere in the thread however I did see that they worked with some other companies like Twitter to share data of suspected Russian trolls and issued bans based off of that.