Do they show up in the game? Even on official rooms?

This is not a troll post. I legit don't know because I've been gone for 2 years and I haven't seen posts regarding these.

Yes after activating the set it puts it on your tori, everyone can see it

As Elite mentioned before, Yes, they show everywhere. Simply activate it and it shows up on your tori. If you wanna see it disappear for a single game and you're too bored to deactivate and reactivate, you can /opt obj 0 then /opt obj 1 so it shows up again.