CROSS BORDER VISA EXTENSION ON THE SAME DAY?

[mixdali]

Hi, we are permanent residents of Canada, however, my one year old daughter is a visitor as she was born outside the country. Her visitor entry visa expires soon. I am wondering if it is fine to cross the US border on the date that her entry visa expires and return to Canada the same day (u turn)? Or does she have to stay in the US untill the next day after her entry visa expires? Thanks