Can parents opt out of homework?

This article came across my Twitter feed from Alfie Kohn and I thought it would make for interesting discussion.
This is a letter from a first grade parent opting her child out of homework for the year. She details her view by relating that she, as a parent, will be involved with her child's education at home and will support the teacher but will not require her child to do homework.
I have many thoughts on the issue but I'll ask the questions first.
How would you handle this situation? Would your answer be different if this were from a Middle or Upper School parent? Can parents opt their child out of homework?
 Let me know what you think?
Here's the link:
http://alfiekohn.org/teaching/hwletter.html