So no bees? I completely agree with @Eva's suggestion. Wax moth larvae can burrow into wood, but they cannot survive freezing. If you see holes in any of the wood, about 1/8" across, they definitely have larvae. However, you don't need to worry once you have frozen them - they are toast, ermm frozen toast?
Sounds like the guy is being excessively honest to my mind. Wax moths are not a major pest in a strong hive, just a minor nuisance. The bees control them 99% of the time. It is only if the hive is weakened that they become a messy problem.