Lock Access to Parent Tasks

We use parent tasks as a way to summarize sub tasks, without assignments, hours, etc. for the parent task, which I assume is how it's intended to be used. However, users are able to log time to the parent task, add documents, etc. which is confusing and also messes up the summing that the parent task should be done. I know there is a way to change sharing access to all of the parent tasks on a task-by-task basis (extremely time consuming), but i think it would be very helpful for all parent tasks to have some form of limited access as standard.