This sort of question works well for assessing senior / lead skills. For example, when asked how to go about replacing PostgreSQL with MongoDB, it'd be okay fo

This sort of question works well for assessing senior / lead skills. For example, when asked how to go about replacing PostgreSQL with MongoDB, it'd be okay for someone fairly junior to either give a straightforward answer or to turn their nose up and say "eww, no" - but you'd expect someone with more seniority to instead flag that it was an unusual scenario and ask for more detail. Prepare a vaguely-plausible reason (eg. "we're storing JSON documents and the team are more comfortable with Mongo's tooling"), and this can form the basis for a productive discussion which you can drive in whichever social or technical direction you feel is most appropriate.