> Any stenographic system that you have the code for can be trivially defeated.

They're giving you an oracle regardless, which is almost as good. Take LLM output, make some modification, ask the detector if it's LLM output, repeat until you learn what kind of changes you have to make to defeat it.

Or don't even bother learning what to do, just make arbitrary changes until it says it's not, so when the person they're submitting to does the same check it says the same thing.