Most outside food is OK, but not beverages, except milk or juice boxes: “Food brought into the ballpark must be wrapped, bagged or inside a container. Items such as apples and oranges must be quartered. Personal food items cannot be carried into any of the restaurants, lounges or suites.” http://seattle.mariners.mlb.com/sea/ballpark/information/index.jsp?content=guide
jissy, I hope you quartered your apples! :)