Adding to Brian's comment-Answer. Several months ago, even though Stack Exchange doesn't seem amenable to subsite-specific changes, I was triggered to idealistically shoot off the following feedback via the Contact link. Their reply was so stock that I don't remember what it said.
This feedback will need to be fleshed out (for example, I've not explained what's unique about our situation, and focused exclusively on PSQs) if it is to be properly submitted as a feature request. Perhaps it could be collated and summarised. I have redrafted it (no mention of the EoQS as it is punitive, non-universal and non-timeless), and am leaving it here for now. (To avoid unnecessary bumping, the latest edit of this letter/Answer is probably here.)
Please also refer to Martin's comments here.
Feedback: Mathematics Stack Exchange acutely needs a site-specific notice
To a casual visitor who has just stumbled on Mathematics Stack Exchange, it is simply a forum for asking mathematics questions (yet it is really not); understandably, students in search of homework help continually deluge this site with “problem-statement questions” (PSQs) that very quickly get downvoted, closed, and deleted by the community who additionally then have to manually issue, in the Comments section, friendly reminders to the culprit.
Now, few people actually read Terms & Conditions or instruction manuals; likewise, it is unrealistic to expect that visitors will have read the Site Tour or anysuch before posting their PSQ.
And while first-time posters are currently flashed a generic “Asking a good question” modal window after clicking Submit, the message may be ineffectual, appearing too late—a user, ready to fire off their PSQ, is inclined to wave it off as another T&C—and failing to communicate the key point about site standards, that is, that PSQs, being deleterious, are unwelcome.
To be clear: PSQs severely degrade the quality of Mathematics Stack Exchange, as they add noise and obstruct good questions from surfacing on Google. Moderating them at the current volume squanders the community's limited amount of energy, time, and attention, and competes with more constructive participation on this website.
To curtail the abovementioned endlessly—and needlessly—repeating routine vitally requires a design fix. Users are much less likely to start composing any PSQ if this subsite's homepage simply contains a prominent link to Guidelines for Attracting Answers, which sums up this subsite's ethos and conveys that its goal of being a useful repository of mathematical Q&A conflicts with being a homework service. This prominent link need neither be glaring nor break the visual consistency across Stack Exchange sites.