As common citizens, we receive notes of higher denominations from various individuals in our day today activities. It's practically impossible for us to ask each and every person to keep track of the serial numbers of such notes. In the ATMs also, we get such notes without any evidence that they have been withdrawn from a particular ATM. However, some government departments like the P&T, railways etc. insist that the customer should jot down the serial numbers of the notes in the respective applications. This is a practice followed only by some offices even within them. In one case, I requested for the instruction before jotting down the serial numbers. I brought to their attention that non-acceptance of the currency notes may be a criminal offence and I shall be free to register a FIR with the jurisdictional police station. I also informed that I shall definitely write the serial numbers on the MO form, Railway application form etc. if there are instructions in this regard from any agency of the GOI. After a lot of argument (not heated), they accepted the notes. But on other occasions, I find that arguing with them would be more time consuming than writing down the serial numbers of the bank notes. What if one of these notes is really fake without the knowledge of the customer. And why is that the departments not issuing fake currency note detectors? I was wondering how far this practice is correct?