If it were an optional feature that could be enabled or disabled by the admin, that would be fine.

I don't think locking the start date and times is a good idea. Maybe there is a better way to do this, but we have always momentarily back-dated most advance stories by about a month or two in order to get a live link for scheduling on Facebook, then immediately change the date to the correct future publish time. Locking the date, or making changing it by permission would make this more of a hassle or next to impossible. Our workflow depends on this ability. If there is a better way for us to get live links please share, but even so I would not like to see start date and times locked this way.