[Erick Estrada]

Originally Posted by PsYcNeT

I just assumed

Spoiler!

they're a bare minimum management group (eg cleaners only show up before a booking) and the previous rental(s) were supposed to have already ended, but no one goes to actually verify if the clients left

Yeah.

Spoiler!

That's likely it. I originally was fixated on the booking part because I felt someone was double booking on purpose to get people into the house. The further you get into the movie the less that theory works as it seems like it was pure luck out of convenience to move the plot.