On the car is a label: “In the car a child, baby on board.” But, fortunately, the inscription is increasingly found: "In the car is an adult, and I also want to live."

I have two questions about this:
1 - why does the author make happy sticker about an adult in the car, before he thought that cars are driving empty?
2 - if the author is so angry with the sticker about the child, why he did not read it, why the duo are obliged to glue it (so that the team of doctors knew that there is a person who does not understand anything, can not get out and is inclined to hide under the seat at the time of fear).