The issue, obviously, is where the rules are stretched beyond anything they could possibly have meant. But even in those cases, the perpetrators - the global companies paying minimal tax, for example - are obeying the rules as they are set out in acres of small print. To "crack down" on tax avoidance is like cracking down on eating, when what you mean is that you're against over-eating. Really cracking down on tax avoidance could be achieved more effectively by cutting out swathes of verbiage from the rules, than by demonising companies and individuals who are doing what the rules allow them to do.