...is dangerous. Well-meaning parents take the advice of "experts" such as the website that hosted this article seriously and suspend their own instincts. The toddler should be home with her mother, not dropped off. She is screaming because she is signaling to her mother that being separated from her mother is painful to her, is running counter to her basic attachment needs and is an alarming, emotionally dangerous situation. The authors do not know the damage they are doing by encouraging parents to just leave their child and let him or her cry. This insensitive behavior goes against the mammal attachment cycle and against every most basic mammal instinct!
Trust your children and do not turn them over to others to raise them!