The only way to avoid the bag check line is to not carry a bag. However... some things to remember when you're at the park. Bag check tables are 2-SIDED which means that even if everyone is lining up on one side of the table, you can go to the other and by-pass that. You'll get some dirty looks, but you're not doing anything wrong. If everyone is lined up properly look for the line that has the least number of strollers in them as well as the shortest line/smaller bags per line. You should have your bag un-slung from your shoulders and all pockets and zippers open and you'll breeze right on in.