Currently, a user only needs 15 reputation to flag a post. They are allowed the option to flag a post with a custom moderator message.
However, on some of the heavier-traffic sites (Stack Overflow is the context I'm speaking from), we are receiving flags from the poster which request help, such as (but definitely not limited to):
this is an project in which i am working please provide suitable link?
And my current favorite:
Plz Reply Fast..
These are obvious misuses of the flag system, and contribute noise overall in their use and handling.
With that in mind, I'd like for a bar to be set based on rep which disallows a user to use a custom mod message when flagging a post.
What that bar should be, I'll leave as an open question, but I think it should be considerably higher than the 15 rep required right now to flag overall.
In regards to Robert's answer about being a teaching moment, I agree, it's a teaching moment, and that's what we're currently doing.
However, in these moments, the user is so bombarded by everyone else on Stack Overflow that a moderator declining on top of that would turn them away. I'd also argue that the person asking probably doesn't even know what they're doing in this case, and is just flailing for attention.
While we are there to provide teaching moments, moderators aren't the deus ex machina mechanism for Stack Overflow in these situations (for others, we absolutely are).
I don't see why we should give the impression with a big ol textbox that screams "this box will grant any wish you desire".
(Note, this is somewhat sarcastic but an actual custom message on a mod flag)
In regards to reputation, the bar might have to be set for 1.5K+ users, as this flag just came in from someone a little over 1K:
May you need authorization from the group owner so that you can view the group.