Continuing the discussion from Ability to force subscription to a category:
There is a solution for making all new users watch a category by default (and users can change that as they like).
There is also a solution to force users to watch a category based on their group membership (and users are not able to permanently unwatch that category as long as they are a member of the group that triggered the watching).
What I am missing is the ability to make users watch a category based on group membership once (i.e. when they join the group) but not enforce if they choose to untwatch. I suppose this would be a matter of extending this plugin to make sure that every user is forced into watching any particular category only once:
Or is there an easier way?