You may want to read it but is there anything you can change, if anything negative goes into the recommendation? If you don't check the box, the admissions office may (or may not) doubt the validity of your recommendation. I'd think you have very little control over the former but the latter could work against you.
I don't know. The student working in the admission office says they don't really care whether you waive your right to read the recommendation or not.But if so, why do they ask?