Don’t overthink it. I bend the rules in my communities quite often. The case that happens most often is somebody posting a duplicate of a news story. However, it is usually one or more days later and the new post usually picks up some comments from new people that didn’t comment on the previous post. I often let those slide. As long as people are trying to constructively engage in the community, then I give people the benefit of the doubt.
It also depends on the community a lot. The anime community on lemmy (!anime@ani.social, shameless plug) has been super chill overall. I think it’s in large part due to the lemmy userbase skewing older than your average social media user.