My DD13 went to Disney in December with a broken arm. We were also worried, but nothing was ever said on any ride and she rode everything, including Space Mtn., Splash Mtn. (covered it up to keep dry), Rock'nRoller coaster, Tower of Terror, Mission Space, Test Track, etc.
The only ride she wasn't allowed to ride was Dueling Dragons at IOA, but she did ride Hulk, Mummy and every other rided at IOA & Universal.