You are correct but see my disclaimer at the end of my post. By not mandatory I was simply referring to the basic science classes (i.e. physio, pharm, etc). Obviously the OMM, labs, and all other doctoring classes are required.As far as I know all schools have required attendance in labs... especially OMM. BCOM does not have required attendance in basic sciences. ACOM has an 80% attendance requirement.
Edit: I would be hesitant to matriculate into a school with P/F due to the upcoming merger. You want to show that you are a top performer to get those increasingly competitive residency spots.