Will you please post the link to the thread & Post #?
That hasn't been what was reported in the past. Numerous posts about resort activities in the past & non-resort guests attending, but usually just resort guests know about these activities, people on the Dis, or those that follow certain bloggers that are on the Dis. However, this has been a year of changes at Disney. With that being said, except for pool hopping, I'm not familiar with Disney restricting guests to enjoying "free" activities/events at resorts. Lots of people go to the free stuff at the GF. Also, unless there are other changes this year, Halloween activities have typically been at Value, Moderate & Deluxe Resorts, so onsite guests wouldn't have a problem.