As a taxpaying American, it offends me that my tax dollars aren't used to adequately protect our food supply, forests and overall quality of life from pests and vermin brought in by travelers and un-inspected shipments from other countries. I've lived through a time when large urban areas were subjected to aerial spraying of pesticides to eradicate imported pests - medflies in that case - because of the major threat those little flies posed to the economy of California. America's native trees are being severely damaged by pests such as the Asian longhorned beetle, Dutch elm disease, hemlock woolly adelgid, and others. Brown-marmorated stink bugs have gotten into thousands of homes in my state, and then there are bedbugs, which I would hope disgust every traveler.

Maybe the OP's apple didn't contain pests, and probably it didn't. But if we give a free pass to one lunch bag because the person carrying it forgot to look in it, how do we have a credible agricultural inspection program? IMO threats to our food supply and economy from pests are a far greater threat to the nation than the small chance of another shoe bomber.