&gt; legally<p>Tax laws are so complex that we don&#x27;t know if some tax avoidance schemes are legal or not.  The accountants selling them claim they are legal.  The tax authorities sometimes claim they&#x27;re not legal.<p>Ideally they&#x27;d go to court and get a ruling, but that&#x27;s expensive and regulators tend to avoid court if possible (at least, in England they do) and so we have &quot;agreements&quot; where a scheme is deemed abusive and some amount of tax is repaid.<p>There&#x27;s no prosecution; no sentences; no convictions.  These repayments are not fines.  So it&#x27;s hard to call that illegal.