Just giving my though on this, It’s a good idea but it will maybe launch a “Karma War” from some people to answers all the questions, with a risk of bad answers, just to get Karma (If the OP of the questions mark as answered, It gives Karma nonetheless.
In a more “aggresive” way, we could also setup a small bot who read tag and associate it with the maintener mail on package.txt and send periodic summary of the number of unanswered new questions about the package (or make a post on a specific Discourse channel).