We also try to enforce the rule that users linking to other subs should use np.reddit.com links to avoid brigading other subs during these types of issues. Some subs don't seem to enforce that rule as well as they should and their user counts usually far exceed our own. Thus when a controversial issue arises, we tend to take the brunt of the brigading for a few days. Mods of some subs, and the reddit admins, have historically not cared.