"They came to your stadium to support their team, not to get yelled at or have stuffed animals thrown at their 7 year old son. Just enjoy the game. Be better people."
Last game I attended at Rice-Eccles we were bombarded with "I hate ___ Mormons" and "___ BYU!" by a kid sitting directly behind us for four full quarters. We asked him to be mindful of the kids sitting within earshot and his friends tried to calm him down, to no avail. But yeah, I'm sure he got a stern talking-to afterward by an ashamed Utah Fan No Matter What. Then after a brief pause they both acknowledged that BYU fan behavior is the real problem.