How is public financial exposure different from living in an affluent area, having an expensive car, etc, etc?
On the other hand, someone driving an expensive car is not necessarily well off, there are quite a lot of people living paycheck to paycheck that drive "expensive" cars.
Kidnap? It seems a little ridiculous for most cases.
I know a guy - we'll call him Mr. Frugal - he's worth, I'd estimate, $5 to $10 million based on what I know about his income and assets over the last 30 years (I know a fair bit to make that estimation). An old family friend, he's in his 70s at this point. He built his wealth from nothing, very slowly, and is a notorious penny pincher (the most extreme version of it I've ever seen). He lives in the same house he has owned since the 1960s; it's worth $150k-$175k today.
This man would be a very ripe target for any number of schemes. Targeting his bank accounts / investment accounts / personal identity, credit, and so on. That's entirely ignoring any kidnapping or blackmail type risks. It doesn't take more than a few moments of consideration to understand how his finances being made so public would make him a target for all sorts of criminals. That despite the fact that he lives very modestly and there is nothing in his home to indicate such wealth. His wealth is held outside of his home, and that's where you would target him. Frankly, given this is HN, I think it's pretty silly obvious that the physical contents of a home often are not the best target for thieves / criminals today.
They become millionaires and stay millionaires because they don't change their frugal spending habits.
Now certainly these people living modestly don't have assets at home that are juicy targets, but they would be juicy targets for kidnapping and extortion.
If they don´t - someone else will take their stash and have fun with it.
Win-win.
If tomorrow nobody could keep it quiet, it doesn't mean the 60% would all get kidnapped, because today the 40% aren't getting kidnapped.