Chances are he knew Amy would discover something, he wanted her to follow the crying girl and gain info on the Smilers and Voting Booths. Also this is very early into the 11th Doctors life we may find he is a very different Doctor and is a hypocrite ( telling other not to do something then doing it anyway ) or just changes his mind a lot.
He did something unTennish and to an extent unNinish. But not unDoctorish. The Doctor changes and his opinions and ways of acting change with him.
Different Doctor, different way of doing things.