What would be some ways to prevent some users from accessing a particular topic?
San this be done without making a new member group?
There is no core feature in SMF to do this.
Writing one, depending on the goal behind it would potentially be very difficult.
What are you trying to achieve exactly? Why block a user from a topic?
Move the topic to a board those users don't have access to. Simple, and how it's meant to work.
The reason I asked the intent is because there are cases where troublesome users need a timeout from a given topic sometimes, and that can be a real pickle to solve.
I suspect trying to implement this just with permissions may not be so simple depending on what problem is actually trying to be solved.
A board has some "homework" for some users to accomplish.
A member that doesn't need to be there has made a few nuisance posts. Until i sort out their needs, I just created a new membergroup 'tempblock' that duplicated all permissions and such of the general members and removed that board from its permissions.
That would be a handy mod: a temporary array of id_members to notview/notreply to any particular board or thread.
No time to investigate that but a thought
That would be a complex mod since you have to prevent them not just viewing the topic, but potentially any *other* way to access the topic - RSS feeds, recent posts, search, profiles, SSI, and pray all your other mods respect that.
This is why the boundary is board based rather than topic based - fixing the boundary with permissions is far easier at a higher level.