Assessments not at night?

Having just gone through accreditation recently at the facility I work in, I cannot understand how assessments by the accreditation team can be THOROUGHLY assessed in a time frame of generally 2 days from 8am to 5pm.

What about the evening and night shifts? Even though it could be said that morning shift is the busiest time, evening shift too can be a tremendously busy time.

Aged care facility staff work 24/7, so how come assessments seem to be only done during the day?