I remember one class where the aide had told me before school started about a firm rule; only one kid at a time was allowed to leave the room to use the bathroom.
Later when she went on her break a pair of boys, one in a wheelchair, came up to me and the one who was walking explained his friend needed a drink of water.
"He needs my help to reach the fountain because he's in a wheelchair," the boy told me.
I replied that all the fountains at the school were low enough for him to reach.
But the boy persisted. With a pseudo-sympathetic expression he insisted his friend really needed his help because of his disability.
In tones laden with sarcasm I replied, "Aw, the poor little crip."
The whole class burst out laughing and the two boys returned to their desks with bright red faces.
I wonder how many other subs had actually fallen for that trick.