I have not experienced this personally, but someone I met told me they have encountered (or maybe also heard of) candidates who were lip-synching someone else's voice to answer questions during an interview. Basically, this person was warning that we should pay attention to a candidate's lips to make sure that they are the person who is actually speaking because there may be someone out of sight of the camera who may be providing competent answers. It doesn't surprise me because a lot of these remote or tech jobs are in high demand; but I don't understand what the cheater who actually gets hired would actually do. Part of me thinks they may actually be hackers or foreign agents.