To address your question of IF, my original post was a direct response to what @
WDW1974 posted. Since he's a reliable poster who has first hand knowledge of how the system works I believe him. That doesn't mean the system wont change. Hopefully someone comes to their senses and restricts that info when this gets rolled out for real.
In answer to what the problem is, I have a right to my privacy. Put aside any of the issues with bad people and crimes. Those were just extreme examples of things that could go wrong. When I decide to take a Disney vacation and make reservations for rides, shows and meals I don't want random people who don't need the info potentially knowing my plans. When I check in, the person at the front desk will know how many nights I'm staying and how many are in my party, the ADR reservation people know my dining plans. They have a reason to know to do their job. Joe Bob just needs to know what I want for dinner tonight so he can serve me my food and bring me my check at the end. No need for him to know anything about me unless I choose to share it. That's the problem for me.