In addition to other arguments, the families of 4th graders are boosting local economies by spending money on hotels, restaurants, AirBnB's, tourist attractions, tolls, car rentals, camping supplies, supermarkets, food and gifts sold within the national parks, and so on. My son is in 4th grade. We could have flown to Europe this summer, but instead we spent over $4000 on a trip from the Grand Canyon to the Rockies. Best experience of my life... all because we could save the $20 entrance fee (which I donated back anyway). Thank you taxpayers!