how would a fake wallet work then assuming the deal is done in person at a police station
or in a bank etc to negate the risk of robbery by either party ?
When you have a briefcase full of cash, a police station is the last place you want to go. There's a 100% probability your money would be seized. Even a bank isn't safe. In most countries nowadays, banks aren't comfortable handling large sums of cash. Only Switzerland remains safe.
maybe they do that where you live but in my country you are free to bring bundles of cash into a bank ,use the automatic counting machines and then give it to someone else etc and the police dont steal your money unless you have done something wrong and they can prove that
What I describe is the actual situation in the US, the UK, France, Italy... In several European Union countries, it's illegal to carry more than €10,000... sadly, that's the world we're living in. Most often, you see panels warning you about it at the airport. If you have more than €10,000 in your pocket, they must be declared upon arrival, meaning that if you get caught with a lot of "undeclared" cash, you'll be f*cked.