Under Internal Revenue Service (IRS) regulations, federal taxes on gasoline and diesel fuel do not apply to sales of fuels for marine use. Marinas that sell tax-free fuel must obtain a "637 certificate" from the IRS. Young obtained a certificate for his business, a marine retailer in Marco Island, Florida. The IRS believed Young never used the fuel for marine purposes, but sold it in cash deals to truck stops and service stations that should have bought fuel that had paid federal taxes.

1. The IRS could x-ray the FedEx packages without a warrant, but if the FedEx notice did not say anything about contents being subject to search, would the IRS have been allowed to x-ray the packages without a warrant?
2. Suppose Young had been carrying a briefcase filled with cash and was driving along the highway in Florida. Could an IRS agent stop him and demand to inspect the briefcase?