This is extremely dangerous. If I were you, I would put this in writing to Disney. There was a 20/20 episode about pool vacuums and drains--children can be caught in them and drown, and can even be disemboweled by them if they sit on them. Not to sound alarmist or disgusting, but children have died this way.
Don't take it lightly--a letter to management with the date and time noted is in order. It is lucky no one was hurt.