Link (Thanks, Al!)
Just this past Friday a Cast Member watching the security cameras noticed a woman in the back of a boat throwing a powdery substance into the lavishly decorated sets in the cavern scenes near the beginning of the ride. Even though Pirates is a 15 minute long ride, by the time the lady spreading the substance returned to the loading area Security had yet to arrive.
The college age Cast Members operating the attraction knew that legally they were not supposed to detain anyone, and when they confronted her about what she was doing in the cameras she told them she was only throwing baby powder around. The woman quickly disappeared out the exit, never to be seen again, but she'd actually left more than baby powder all over the Pirates of the Caribbean.
Security and the police finally arrived, and the ride was shut down on a busy afternoon of a holiday weekend. The ash was identified by the Anaheim Police as cremated remains, and the custodial department found most of it all over the "Captain's Quarters" scene in the caverns. The woman had done a very thorough job of spreading the ash everywhere though, and after an hour of cleaning with the HEPA vacuums there was still work to be done.