I'm a mod of quite a few subs. We have to submit spammers to /r/spam. It is a bot run sub that basically does link counts from your history, if you hit a threshold, you will get shadowbanned. Submitting a user there who has been around for say 1 year with 250/250 karma, they probably will not get shadowbanned as they don't fit the algorithm. Mod a sub for long enough and you can instantly look at an account and tell whether or not they would get shadowbanned. There are tons of egregious spammers on the site who will never get banned because they don't fit the mold.