No, it's when a benchmark becomes a target. You might have a private benchmark that you tell no one about. Would you not trust it?

Good benchmarks are costly to build even for mid-large corporations. And once the benchmark is used on models you really can’t tell if the problems would be scrapped for training

I was speaking in general, not just about AI.

Any benchmark that has a selection condition can be discovered. The more money involved, the more effort that will go into discovering said benchmark.