When you want to schedule the job, do you need to provide the package password in the agent configuration? If so would you need to restrict access to who can view the agent ?
If the package is encrypted, you can pass in the package encryption password via the dtexec /DE switch (in SQL Agent, or most any other scheduling utility).
... may not go far enough if there are many users with elevated priviledges.
Potentially a privledged permissions problem. :-D