They dont. It's a lie. They sell unsold student tickets to the general public.
They just want more money because those tickets cost more than student tickets.
This way they'll be able to eventually take away another student section and maybe one day they hope to be able to sell all those high value lower bowl seats to the general public.
"How do we increase the atmosphere at the Ralph?"
"Let's make it so a student can't sell their ticket if they are busy that day."
"How about to another student like....always?"
"No, not even to their own classmate."