Some time ago a new feature was added to SE software, which allows customizing a message shown when a user is trying to add some blacklisted word to a post. See this post on meta.SE: Allow adding a specific message / guidance to blacklists
You might have noticed that a customized message was added when blacklisting (exercises-and-solutions) tag.
I do not know what are the requirements on the text used for such messages, the only information I have is from here:
Tim Post said that it should be about a couple of lines long within the pop-up, and that pop-up is exceedingly narrow.
The same thing was discussed when the algebra tag was blacklisted, but it was not possible to customize these messages at the time.
Should we request adding some message to some of the currently blacklisted tags?
I should thank to Arthur Fischer, who provided me with the information I quoted above, when we briefly discussed this in chat.