Joe, the Roles that are assigned to people are where security comes into the front. As I just learned the other day, you can create a different Role tht allows Users to a particular capability without compromising other Roles. You can assign that Role to any number of Users to complement their existing Role.
The issue I think I am seeing with your code hack might mean that as general applied code it compromises the security of all forums, not just the ones you want anyone to access. So be careful with that hack - check it to make sure it is not having an unexpected impact.