For the most part, not really.

These bills were withdrawn from the bank by Person A, and later deposited in a different bank by Person B, who is a flea market vendor (you know this because financial records and other transactions already tie them to the flea market organizers). You can reasonably infer that Person A attended the flea market in the intervening time period and bought something worth that amount from Person B.

It would only start to become difficult to track when multiple person-to-person cash transactions are done in a row – as in the case that Person B spent the cash on drugs from his drug dealer instead of depositing it in his bank account.