Caramme
Gosh, this post made me angry. So, OP, who do you value most, your dogs or your grandchildren? Have you seen how many children are attacked by dogs? Your grandchildren are too young to understand how to treat animals so no good blaming them for being unruly. Yes, the parents should have taken some responsibility, but you saw the danger. It is your home, your dogs, your grandchildren - and you knew they were not safe. So why were the dogs not locked away from the children? What were you going to do? Wait until one of the dogs bit the toddler’s face off?
Well quite.
OP I think you are seriously missing the point. Two very small children not used to dogs (and why should they be?) do not behave appropriately with them - well, there's a surprise! The responsibility here lies with you fairly and squarely.
They are not brats - they are small children. They did not "disrespect" (lord preserve us!) your dogs ; they simply behaved like children - what were you expecting?
The children and dogs should have been kept completely apart, as the responsible dog owner grandparents on here would do without a second thought.