It shows a guy texting, and then another guy, WITH A HOODED SWEATSHIRT and a back pack, getting ready to board a train. The message was to stop, look around, and think.
I don't know who sponsored the sign, didn't have time to stop and look at that, but found it amusing that even the government, unknowingly, realizes that a hooded sweatshirt can be used to hide your face. Think of all the Robin Hood movies you've seen where Robin or one of his merry band disguises himself as a hooded monk.
It's hell to be a rational person in this country today.
You will not see a picture of a muslim woman with her head covered though. Muslim males can use the same disguise and no one will check them or complain about it.
In the Middle East they give you strange looks if you are in a public area with a backpack.