The Ban Bargain is a technique to temporarily ban users, to stop them from complaining about being banned, and to curb their unwanted behaviour. If a user makes a comment worthy of a temporary ban but not a permanent ban, initially give the user a permanent ban. The user will then beg to be unbanned in modmail. Tell them you are willing to shorten their ban, if they are willing to never do whatever they were banned for again. They will happily agree, and think they were given a second chance, when in reality you were only going to temporarily ban them, anyways. Make sure to temp-ban them for long enough that they will remember the ban next time they go to make the same type of comment, but not for so long that they completely forget about the subreddit.