Cash eventually passes through banks: Can't the read the serial numbers, and pretty easily at this point? It's not like tracking credit card or Venmo transacti

Cash eventually passes through banks: Can't the read the serial numbers, and pretty easily at this point? It's not like tracking credit card or Venmo transactions, but if you take out $500 and give it to someone who deposits it, and if they read the serial numbers, it's clear what happened.