This is a pretty uncommon scenario, though. Making everyone work on-site on the off-chance that someone will fake an interview seems like a severe over-reaction.
I guess it's possible that if the new hire isn't legit, they might send a better person, but since those sessions were quite regular, plus they were also doing "remote stand-ups", it would be tougher to always be able to send the same replacement and / or not get caught.