On a global scale, on an accumulated basis, there is certainly some need for tax-havens, meaning for some Sherwood Forests

Not everywhere, but truth is that in the majority of countries, the need of many citizens for a safe-haven, a Sherwood Forest, so as to escape from bad Prince Johns’ Sheriffs of Nottingham who, skimming them, just waste away fiscal income, surpasses by far the needs of all citizens for Robin Hoods able to skim some of the “filthy” rich. 

You have to make up your mind whether you are a Sheriff of Nottingham, or a Robin Hood, you can´t be both. 

Nothing as effective against tax-havens than tax-heavens

There is an underlying and never questioned premise that guides most discussions today, and that is… If all profits are taxed and all taxes are paid then the world is saved. 

I do not want to be a party pooper, and I definitely do not suggest, much less instigate, we should evade paying our taxes, but... are we really sure that a tax paid will be more productive than a tax withheld? 

What if we all have to go the route of an economia sommersa, and not pay taxes, in order for the world not to collapse? Do we not at least owe our children and grandchildren asking that question? So as to at least put some pressure on our governments?

There was a time when indeed a Robin Hood tax was contemplated but that has now only evolved into a questionable Sheriff of Nottingham-Prince John tax.