The "err on the side of safety" policy is more error than safety, but it is pretty standard. Put yourself in the position of a CPS agent. First of all, they are in the business because they want to protect children. The worst case scenario that keeps them awake at night would be to walk away from a child who needed protection and the child ended up hurt or worse. They would rather break up a thousand loving families than have a single child killed by an abuser.
Don't expect help from lawmakers. Going up against child protection is a great way to lose an election. I can't think of a worse position a candidate could take.
Preponderance of evidence? In the world of CPS, it is more a matter of being guilty until proven innocent beyond ANY doubt.
Beyond that, most child "experts" believe that they can always get a child to say the truth. They feel convinced that all they have to do is be the friend and confidante that the children will open up to. If the child is against you, you are essentially doomed.
When my daughter first made her allegation against me, everyone in her clinic assumed my guilt with no ambivalent second guessing at all. I could tell by their tone - their minds were set against me. When she recanted, it put them back on their heels a bit. They had been so sure.
The tragic mistake that CPS makes, is that they are not erring on the side of the well-being of the child. If the allegations are false and if the lies have been instigated by a caretaker in the context of a custody dispute, the child is at risk of great harm if they are returned to the emotionally abusive parent. Not only does the child lose his or her parent, but the caretaker that is hurting them continues to do their damage.
For this reason, I urge people in your position to continue to fight for the safety of their children. What about supervised visitation? Is that an option?