Is that a real name for a real parenting theory? Detachment parenting?
I don't necessarily think that is "detachment" except the part where it's about responding to crying. If you know the baby is not hungry and is dry at bedtime, and they fuss, let them fuss. But if they are crying, it means they need you. It's the only way to get attention. They have a need, and you as the parent are obligated to care for that need. And yes, babies do need to know their parents will respond to their needs - even needs of belonging and knowing there is another person around.
Personally, I've never believed in allowing baby to sleep with the parents except in the cradle in the same bedroom during the first 3-4 months. After that, they should be in their own room with a baby monitor. That is not a "detachment" issue, though.
As a parent, I think it is important to form a healthy attachment with offspring. This initial attachment has a significant impact on their future romantic relationships. Secure attachment does not come from letting them sleep with you, breastfeeding (although it is a contributor) or ignoring their pleas. It does come from being responsive to their needs, spending time with them, caring for them, gazing at them, and as they get older, playing with them and teaching them.
Here are a couple of links about attachment theory:
Attachment Theory: How Early Attachments Shape Behavior
Attachment theory - Wikipedia, the free encyclopedia
The practice of "detachment" can put your children at risk of attachment disorders. I've worked with a few youths with this disorder, and the social problems they have as a result are very, very unfortunate.