A very common, and very important, kind of known asymmetric ignorance case arises when non-experts with respect to some domain, D, interact with people who are experts with respect to D. Harry Collins and Robert Evans discuss what they call 'external' expertises that we all have and can deploy to help judge whether some individual is an expert or not. They focus on what they call "ubiquitous discrimination", which is "what we have all been learning since we could speak" and which is "just a particular application of our regular judgments about friends, acquaintances, neighbors, relations, politicians, salespersons, and strangers". This chapter argues that in strategic expertise contexts, testimony is not default justified, testimony is not knowledge transmitting, and non-reductionism about testimony is implausible. And refusal of an expert to be included or a decision by an expert to contest all the entries about him be epistemically useful: suggesting that significant skepticism about that expert's testimony is probably warranted.