What's the point in kicking people off Caltrain if they have a monthly pass

Guy scans his clipper card and it declines. He says he had just moved from Canada and was not used to caltrain. His company had just given him a monthly pass and he assumed it was automatic.

The worker was rude, tried to give him a citation and couldn't because his ID was Canadian. So he just got kicked off the train. Wtf! Having a pass means his ticket was paid for! It made me so mad. Welcome to the bay I guess