Never wake a sleeping baby!

I have always been told, "Never wake a sleeping baby!" Well, obviously our dog, Piper, does not know this rule. She was sleeping in the boy's room just a few moments ago and heard something that must have made her think she needed to defend us.......or she was just startled out of her sleep. Either situation, she barked, loud! And next thing I know, Baby Bo is crying. Never bark in a room where little one's are sleeping. In fact, she is fussed at for barking in the house when either of the boys are sleeping. I think he has finally drifted back off, but I am not happy about this!