If a foreign person engages in a transaction (or series of transactions) with a principal purpose of avoiding the tax imposed under section 5000C, the transaction (or series of transactions) may be disregarded or the arrangement may be recharacterized (including disregarding an intermediate entity), in accordance with its substance. If this section applies, the foreign person remains liable for any tax (including any tax obligation unsatisfied as a result of underwithholding) and the Internal Revenue Service retains all other rights and remedies under any applicable law available to collect any tax imposed on the foreign contracting party by section 5000C.