Detecting dishonest merged-mining pool How would one go about detecting whether a mining pool is being dishonest by performing merged-mining without sharing the Namecoin income with its miners?

We assume that:


The pool is operating normally, albeit pays out only Bitcoin rewards
It merge-mines while claiming not doing such a thing


How could we find out the pool is in fact merge-mining and what are the tactics the pool can use to make our investigation harder?
The only way to know for sure would be if you mined for the pool and you mined a Namecoin block for them. You would find the particular header you had submitted as a share used as a solved, merge-mined Namecoin block.