To your last question, this is why financial institutions are required to report cash transactions over $10,000. There are a number of constraints on how untraceable cash is.
No. Also, there were several recent articles/speeches from various AML/BSA/Fraud folks to lower that amount even further for several purposes including CTR. For better or worse, BSA has become its own industry with a lot of money riding on keeping things annoying to regular people ( and barely doing anything to stop actual criminals, who have skills, patience and resources to bypass all the safeguards ).
