I've seen on some discord servers there is a message, often a bot message, instructing to go to a specific channel to read #instructions before posting, or similar.
I'm not sure what rules the bots follow, is it automatically after the last message (that could be annoying), or is it after the channel had gone silent for a while, etc.
This info is on the channel description but it gets missed all the time (understandably). This channel is constantly mistaken for a job posting channel.
It might be a good general feature for channels that frequently get misused/misunderstood.
On the other hand, its not really a big deal to redirect them either.