Plenty of cases where random traffic stops and airport "additional screening" checks have resulted in cash being seized, even when someone has sufficient evidence that they withdrew it from a bank.
In Civil Asset Forfeiture cases the burden of proof is reversed (i.e the cash is presumed guilty).
Simply having a bank receipt doesn't prove innocence of the cash, and the law enforcement officers who seize it will just do so and claim that you were about to do something criminal with it.
It's on you to prove - in court, by filing a lawsuit - how you came by it, how it was to be used in legitimate activity. Even then, if you 100% prevail, you're still liable for all of your costs for doing this.
If you had to file a Federal case (because local/state authorities can, and will, send it to some federal agency and get 80% of it back in a sharing-arrangement) then your costs for getting your money back are increased even further.
