See my reasons why (as well as a counterargument) here:
http://www.parentscanada.com/school/touchy-subject-is-it-ever-ok-to-take-over-your-kids-homework
P.S. As a primary teacher, I don't believe in assigning very much homework at all, nor have either of my daughters ever brought home an unreasonable amount throughout the primary grades. We'll see what happens as they get older!
