إِذَا كَانَ الْمُصَلِّي يُصَلِّي إِلَى سُتْرَةٍ، وَإِبَاحَةِ الْمُرُورِ بَيْنَ يَدَيِ الْمُصَلِّي إِذَا صَلَّى إِلَى غَيْرِ سُتْرَةٍ
That is when the person praying is performing the prayer with a sutrah placed. And when the person praying is performing the prayer without a sutrah, then it is permissible to pass in front of the person praying.