It's a very interesting idea, but in the end it's a moderately-sized number that's light gray over a dark gray background... It seems hard enough to read that the kid would have to stare at the ad.
The whole point is that it's OK for the kid to stare at the ad, because from the vantage of a normal-sized adult, it doesn't look like it's anything related to child abuse.
Except it's just the phone number and quote that are hidden from adults. There's a message at the top about child abuse and a picture of an abused kid that everyone sees.
I think the child looks normal with no injuries to the adults. The bruises only show up to the children.
Message, yes, but it's just a picture of a somewhat sad-looking child in the upper view.