I have a small application in which users are all assigned the "Planner" role. There is not data level secruity, and no security applied to individual data forms - all users are allowed to see all forms.
Recently, I created a new form in Planning and a new report in HFR. However, none of the users, except those in the administrator group can see this form. Initially I did not assign any specific access for the form, since I figured by default all those in the "Planner" role can see all forms anyway, but that turned out not to be the case.
I then went ahead and added a specific user or two to be able to see that form. Still, they can't see the form that I created.
There is no way planners could have access without security being defined on the dimensions and forms as by default they will not see anything unless explicitly grantes access.
Therefore you probably have granted all users some kind of access on dimensions and forms probably via a group, and once you assign your new form and report they will be able to see it. Check what groups they are in via Shared Services and then check the security report for that group on planning. Chances are you will see that the group has permissions assigned to it.