I thought that it was limited to only the members of your group (Kinda wi* wasn't so blatant when someone spun it), but every once in awhile the words will pop up in the center of the screen and in chat that so-and-so spun the group lucky wheel... but they're not in my group. As far as I know, they've never been in my group.

It doesn't happen often, but does that mean that other people can see my spins? I spin every day, and I don't want to annoy people...
I don't know how it is in other groups, but no one really uses lucky wheel, at least not that I've seen. Maybe it just shows the world whenever you spin it?