Bale beat me to the answer, but I'd like to add that the Rumpus Room items can be compared to your basic rollover gear. Por ejemplo, if you have a +pvp helmet equipped for rollover, it won't matter what +adv helmets you have in your inv/closet/hagnks/dc, you'll only get the benefit from what's equipped, which is the +pvp bonus. That's the same as if you have A Jukebox in your rollover clan, and you switch to a clan with a Klaw or Soda Machine; you'll still only get the Jukebox benefits for that day.
I don't know if it might help, but if the Rumpus Room areas were treated similar to "equipment slots", it may make it easier to understand. I recognize they're not equipment slots, but it's the closest thing I can compare it to.