I'm coming to think that the rule of three is important within a fairly constrained context, but that other principle is worthwhile when you're working across contexts.
For example, when I did work at a microservices shop, I was deeply dissatisfied with the way the shared utility library influenced our code. A lot of what was in there was fairly throw-away and would not have been difficult to copy/paste, even to four or more different locations. And the shared nature of the library meant that any change to it was quite expensive. Technically, maybe, but, more importantly, socially. Any change to some corner of the library needed to be negotiated with every other team that was using that part of the library. The risk of the discussion spiraling away into an interminable series of bikesheddy meetings was always hiding in the shadows. So, if it was possible to leave the library function unchanged and get what you needed with a hack, teams tended to choose the hack. The effects of this phenomenon accumulated, over time, to create quite a mess.
An old senior colleague of mine used to insist that if i added a script to the project, i had to document it on the wiki. So i just didn't add my scripts to the project.
I'd argue if the code was "fairly throw-away" it probably did not meet the "Rule of 3" by the time it was included in the shared library in the first place.
For example, when I did work at a microservices shop, I was deeply dissatisfied with the way the shared utility library influenced our code. A lot of what was in there was fairly throw-away and would not have been difficult to copy/paste, even to four or more different locations. And the shared nature of the library meant that any change to it was quite expensive. Technically, maybe, but, more importantly, socially. Any change to some corner of the library needed to be negotiated with every other team that was using that part of the library. The risk of the discussion spiraling away into an interminable series of bikesheddy meetings was always hiding in the shadows. So, if it was possible to leave the library function unchanged and get what you needed with a hack, teams tended to choose the hack. The effects of this phenomenon accumulated, over time, to create quite a mess.