The reason for this policy is security, plain and simple. The stadium wants to make sure everyone is safe and has a good time. It's like when you're at a concert and they check your bag before you go in - it's just a way to prevent any problems.
Now, you might be thinking, "But what about my favorite purse or backpack?" Don't worry, you can still bring those in, as long as they fit within the size limits. It's like trying to fit a puzzle piece into a puzzle - if it fits, it's good to go!
The size limits are actually pretty reasonable. For example, you can bring in a bag that's 12 inches by 6 inches by 12 inches. That's like bringing in a small suitcase or a large tote bag. Not too shabby, right?
Lumen Field Bag Policy: Allowed and Prohibited Items - SeatGraph
