Putting a creative spin on necessary negative imagery in advertising

While working on the Pencils of Promise campaign we several times ran into problems because we were using too much negative imagery to try to "guilt" the target audience into helping. This ad campaign for British Columbia Children's Hospital had to battle a similar issue. They need donations to expand the hospital because it's become too cramped. However, the way they show the negative conditions is in a creative way. Instead of showing their actual cramped space with sick children and helpless doctors, they chose to use optical illusions for powerful imagery that sends a strong message.
Take a look!

Optical Illusions Highlight Hospital's Cramped Conditions