The reason is pretty simple: security. With clear bags, security personnel can easily see what's inside, which means they can do their job more efficiently. It's kind of like when you're at the airport and you have to take your laptop out of your bag - it's just a way to make sure everything is okay.
Think of it like a transparent process (get it?). The clear bag policy is just a way to be more open and honest about what you're bringing into the stadium. And hey, it's not like you have to get rid of your favorite bag - you can just use a clear one instead! It's like switching to a see-through water bottle, it's just a small adjustment.
