We found this was very ineffective at Stack. Urls are very easy to change and spammers rarely stick with one for long.
Not opposed to it, but unlikely to help much, if at all.
For common urls you just don’t like or don’t ever want posted , those are more stable and can work. Like if you decide you dislike sports so much you don’t ever want a link from ESPN.com posted, ever. Or the craptacular w3schools.