There is a post notice for answers in need of support, but I'm unclear as to how that post notice is placed.
If we see something that needs support, what is the process for noting that? Obviously a comment isn't a bad idea, but many times people don't want to comment because they don't want to engage in a conversation or for any other reason.
Is there a process we should follow?
It's a post notice. Diamond moderators can add and remove it. There's no flag associated with it.
Leave a comment requesting the clarification or support that's needed. If it's egregious then also raise a flag for moderator attention suggesting we add a post notice.
“Egregious” here is key. We don't add them to just every single answer that needs additional citation; comments alone can handle that. We use these in cases where we want to step in and send a clear signal to somebody (the author and/or other users): for example, when someone's leaving an answer to a high-profile question making bold uncited claims. If that post notice is on the answer, it's likely either getting improved soon or deleted soon.
It's probably not a flag, but a post notice. They can only be added (and removed) by ♦ moderators. RPG has three 'standard' answer notices and a fourth RPG-specific one, as can be seen in the Data Explorer.
I'm a moderator on three other sites in the network and regularly apply answer notices when I see a low quality answer (often after it has been flagged as Very Low Quality) of which I think it might be able to be edited into a proper answer. I guess you could use a custom moderator flag asking to apply a post notice, but I haven't seen anybody do that so far and I'm not sure what the moderators here think about this.
Here's how this works, based on my experience. This is emergent behavior, not policy, and some of it is probably undesired.
The post notice tends to go (~20% chance) on answers with no-to-moderate citations on questions that are active and that a mod is personally interested in and where the answer is out of left field (this is part of why I think moderator system proficiency matters).
The post notice tends to go (~1% chance) on the inevitable unsupported but upvoted 'popular opinion' answers to highly-active idea-generation questions that aren't being closed.
The post notice tends to go (~100% chance) on all other unsupported answers posted before the banners are put on things where a post notice was placed on an answer pursuant to section 2.
The post notice tends to go (~60% chance) on all answers, regardless of support or lack thereof, where a post notice was placed because of number 2 and the post does not cite a respected published resource (e.g. answers citing personal experience or blog posts for a system where those aren't respected much or "I talked to at GenCon in 19XX and they said X" or "I am and I say Y")
The post notice tends to go (~50% chance) on flagrant opinion answers by high-rep users when those are contrary to the opinion of a mod or other high-rep user, which is practically all the time.
The post notice tends to go (~5% chance) on unsupported posts by users with 3K-7K rep. The chance rises significantly if a user doesn't change their behaviour after receiving a notice.
The post notice does not go on posts by new users unless the post has bad grammar and is wrong. If a post has bad grammar and is wrong and the user sticks around to defend it, it may (~25% chance) get the post notice. That chance skyrockets if the bad, ungrammatical, unsupported post is not at a negative total vote score, but that's practically never (such posts are usually edited for grammar or downvoted into oblivion or both).
The post notice (or maybe a similar one?) goes on (~70%) answers that recommend homebrew without indication that the homebrew has been tested at all on a question where a mod is participating and after the poster ignores comments suggesting they support their claims.
The post notice goes where chat summons it, but I know not the ways of chat.
