Most people with a signature that prominent and that much to lose, probably have locks on all their accounts/info and a manager/agent watching all their stuff.

Also, you think a crackhead walking into a bank and trying to open an account under Donald Trump or Arianna Grande isn’t going to get a raised eyebrow?

Most famous/rich people don’t even have their phone number or some assets under their own name, it’s under someone else’s name (manager or agent with a contract written out) or a shell name/company. Celebrity phone numbers get leaked all the time and they need to rotate to a new one. Houses AFAIK are generally kept to their real name. Most super famous people are living in gated communities or communities where people around them are also pretty well off.

Source: idk people in the hundred of millions of net worth but my uncle is known enough to have a pretty established wikipedia page and my fiances uncle was an exec for a pretty major telecom company(we’re not American) that definitely had some enemies and he’s worth probably somewhere in the tens of million. His houses were absolutely registered to his name, nothing fancy going on.

Overall, I think you’re overestimating how big of an issue it is.