Just as most librarians would say, the library should not be leveled for student check out, so we want our students to have freedom of choice. If you see students are always picking Harry Potter or Capt Underpants, you might talk about the I PICK concept of “what’s your purpose”. If their purpose is to get a book to read with mom or dad, or to just enjoy the photos of animals they love, then they should have freedom of choice.
You will have given them books at their level through your small group/individual conferring to have those to practice.
One caveat that I have experienced is that some of the strugglers I work (especially 3-5 graders) will just look at the front cover to decide if a book is interesting. I think we can help them learn how to read the back cover, maybe read the contents page, walk through the pictures (if a picture book), glance at the text to notice the size of print, amount of text on a page, etc, and how to use those findings to see if it really is one that they are really interested in. We’re not limiting choice, but helping them make educated choices :).