Has trick or treating started? I can't seem to figure out how to do it. I have gone to profiles but nothing happened.

Not sure either. Some accounts have the button, some don't. 

Oh! I found out on most of the ones that don't have the button, there is a little gear at the top left corner of the page, and clicking that once changes the layout so the button shows up. Somrone helped me out. But hopefully this can help someone else as well! Doesn't work on offline people's profiles, but as long as they are on the users online list and have a small trick or treat bag thing next to their name, you can trick or treat at their profile.

Thanks!