I would have been annoyed about being paired with a CNA as well. When I was going through CNA clinicals, I expected to be paired with a CNA and see that role in its entirety. However, the RN role is much broader and requires a different skill set that includes the skill set of a CNA.
I can understand their desire to allow the students to shadow CNA's in early clinical settings for the purpose of learning basic hygiene, bed changing, and mobility (and a whole lot more) if they do not require them to go through a CNA licensure prior to starting their clinicals. However, that should not be the norm for a med-surg clinical in any respectable nursing program. If there are not enough nurses to go around, the clinical instructor should facilitate learning by taking a small group of students themselves, splitting them into teams, assigning multiple students to one patient for parts of the day...there are just so many more creative ways to allow students to get an idea of the RN experience rather than being another body performing hygiene tasks.
Yes, these tasks are important. Yes, the CNA role is important. But that does not change the fact that placing a student nurse with a CNA is not allowing them to see the delegation, prioritization, and coordination that a registered nurse performs in the hospital setting on a daily basis. While yes, you may have to be your own CNA for patients due to short staffing, you still are responsible for the duties performed by the RN.
One clinical - I would let it go. But I would not allow myself to be placed with a CNA the next clinical without speaking up, especially if they are not rotating the nurses around. We had anonymous evaluations every semester - if you do, I would also make sure to note that this occurred in your evaluation and how you felt honestly. Schools do make changes, including clinical site changes, based on evaluations if multiple people speak up.