This is true, though even CNAs have to have some kind of certification and then are hired by the hospital and added to their institutional insurance policy. So even though the basic assisting an overworked RN is pretty easy, most of the students will start without any experience on that unit or in that role.
In practice, my guess is that the students will not really fall into a CNA role. Since they will be there as volunteers/learners, they will probably get pulled into procedures or assigned to more interesting patients/units. Similar opportunities are where I learned a number of basic bedside skills such as IV placement, drawing labs, ABGs, NG placement, etc. I'm definitely not a wallflower so anytime I was in the hospital I was asking to do things. I learned that no nurse gives a flip about doing yet another IV or lab draw (or an RT doing yet another gas) and will gladly let the student try, especially if it's an ICU with a sedated patient.
Like all things, some students will have crap experiences. Others will have fine experiences but not know any better and complain anyhow. Others will have a good experience and realize it and be better for it.
There's no threat of dismissal here, no red flags, no coercion. Believe it or not, preclinical students are so far down the totem pole that nobody gives a rip about what they do or don't do. If anything, this adds paperwork for the admin and still doesn't solve the staff shortage, but they probably feel like they're giving students a unique opportunity to be part of caring for suffering people in a historical time.