Not that easy, since part of their reason for existing is not just as holiday homes, but mainly as ways of laundering money through movable solid assets, which are internationally free, and hiding who they belong to, is in part part of their purpose.

Having said that, I do think that a lot of the super-yacht fuss, is just gesture politics. In that they are not that important to their owners, and the owners may often not be especially strong supporters of Putin. But they do make good headlines, and while the press and public are distracted by the yachts, you can still, quietly, keep on doing business as usual and let the owners move their dirty money through your state banks, etc., with no questions asked.