Where I live teachers/in-classroom workers who are unvaccinated are tested 4x per month and vaccinated are tested 1x. You can draw your own conclusions.
The breakdown is similar on weekends, holidays, etc which suggests that mandatory testing does not skew the numbers significantly in Ontario at least.
But as I said: reported cases blah blah, they paint a fairly clear picture to me but there is a lot of complexity there.
What about ICU numbers?