Believe GPA is the deciding factor at your own peril.
http://www.fairtest.org/university/optional. Not one top 25 school on that list. One of the few better schools is Holy Cross and I can give you an earful how Holy Cross manipulates the test optional submissions. I have been thru 3 college admission cycles, 2014 the most current, so I do know the game quite well. Go ahead and tell umichigan or Boston college, Georgetown your kid isn't sending board scores, come back and tell us how it works out.
