Do you simply have to wait? There's no other pre-requisites? I remember someone saying you need to have sex with the Tess robot in all the rooms with the no-sex sign but that might be for something else.
It was just a coincidence to learn about this. I was lying in bed the previous day without a good night's sleep and saw the news that 1.2.0 had been updated at dawn (my time zone is quite a bit different.), and I woke up tired, but I was trying to find hidden things almost all night.
I also saw that post and was trying to do the same thing, and I fell asleep in the middle, sitting in a chair.
And when I woke up, I saw some guests on the first floor even though I didn't do anything like before, and I took a hint from Hanako-san's event and decided to wait recklessly.
And after a number of validations, I found out that the conditions for the Faith event were to talk to Kent and triggering the event, and just wait in Evergreen.
Perhaps even in the case of the yellow sign we talked about before, his "long" stay at Evergreen to watch the event seems to have been accidentally matched.
What LAGS said means "I didn't expect anyone to find it until the next update" is that when we play this game it takes about 15~20 minutes at the longest, so I guess he didn't think anyone would stay on the same map for more than 30 minutes.