Wow!
We stayed at YC, last August, and every day we went to SAB,
and every day we were checked.
Once you show them your roomcard, they put a colored wristband on you for the day.
So, you don't have to wait back in line to get in.
They had several CMs at every entrance, which I think is 3 entrances.
One on each side of SAB, and one in the middle, by the Healthclub, spa, and bathrooms.
There may be more entrances, but these were the ones I noticed that were open.