If I had to guess at what's really going on here...it's that the landlord suspects the residents of some of these units aren't the people they're supposed to be

If I had to guess at what's really going on here...it's that the landlord suspects the residents of some of these units aren't the people they're supposed to be. Sometimes if someone has a rent-stabilized apartment, they might want to move somewhere else. Ordinarily this would cause the unit to lose rent control status, but if they simply let someone else (e.g. a family member) take their place without notifying the building, they can maintain that status. Just a guess, but maybe this is the underlying motivation for adding this technology. The motivation suggested by the article doesn't really make sense to me. Why would high income individuals want this?