Absolutely this !
In this day and age, the last thing you want is a large chunk of money turning up on your doorstep whose origins you cannot account for.
Its bad enough when you can prove the origins and you have to provide all the audit trail documentation. Ask anyone in the financial sector who has had to deal with compliance questions landing in their Inbox about a client's source of wealth.
When you can't prove the origins, well, "not a good look" as the old saying goes.