For
It prevents interference with parenting styles.
Against
Children benefit from the extra love and wisdom of grandparents.
Anonymous excerpts, translated where noted.
“If the grandparents can't or refuse to respect this, then they get limited time or supervised”
“Grandparents, as the main storytellers in children's life, help fulfill this need. Listening to their stories broadens children's horizons.”
“I figure my kids benefited far, far more from time with the Grandparents than without, and if rule bending is the cost; so be it.”
“If my parents were out of town, I'd put a limit on how often and how long they can stay with us”