Here's the lowdown: you can bring one bag, and it's got to be smaller than 16x16x8 inches. That's roughly the size of a large purse or a small backpack. If you're used to carrying a giant tote or a luggage-sized bag, you might need to downsize a bit.
Think of it like packing for a day at the beach - you want to bring the essentials, like a towel, sunscreen, and a book, but you don't need to bring your entire closet. The A's have got some examples of allowed bags on their website, so you can check it out before you head to the game.
Now, you might be wondering what happens if you show up with a bag that's too big. Don't worry, the A's aren't going to turn you away at the door! You can either return it to your car or check it at the gate. It's like if you showed up to a party with a dish to share, but it was too big for the table - you'd just need to make some adjustments, right?
Oakland A's pack their bags for Sacramento after Coliseum negotiations