I believe for this experiment to be fair it requires an inborn, unalienable physical trait with particular cultural baggage that resonates with the negative connotation of the term. This combination isn’t that easy to come by, and might be hard to invent for those unaffected. “Beta” is unlikely to qualify (not unalienable); “master branch” maybe not (?); “blacklist” is debatable. Something involving country of origin/nationality/skin color might be it though (if the controversial cultural baggage condition is satisfied).