Most have a small bag for essentials when at the pool, beach or Jacuzzi and just keep it there - other than that you cam punch a hole in the key card and wear it on a lanyard
I think the new, updated room keys are actually a chip in the bracelet they give you when you check in... so you don't have to "hold" anything. You wear it. That's how TTR was last time, and I "think" DRM has gone to this by now as well, but someone else can confirm/deny.
correct... your room key is now your bracelet! The greatest invention at TTR since, well since anything. No more worries about placing, misplacing, losing your card (key)!
FYI - Desire Pearl and RM(which the OP was asking about) have NOT updated to chipped bracelets at this point in time and still use the older key cards....
You have to bring your shorts and or bathing suit with you anyway to go in for food so I just leave the key card in my shorts pocket. Easy.