I wonder if this should be codified as a rule of thumb, or an unofficial "law"? One perhaps we can reference easily among our peers.
You mean like Goodhart's Law? (Unless you're being sarcastic)
That's close but not quite.
That says that when a measure becomes a target, it ceases to be a good measure.
My argument is that in the 21st century, a time of great data use without deep understanding, any measure at all will inherently become a goal to be gamed.