There are several ways to get your funds locked because of this: 1. Failing to send this requested message when submitting the transaction from the wallet, will surely get your funds locked and requires contacting the exchange customer support and you should expect a long delay until getting a refund. 2. Sending an encrypted message when the exchange asks for plain text one or vice versa is another popular way to lock your funds. If the exchange does not specify otherwise we recommend that you send the message as plain text. 3. Sending ARDR/IGNIS, from one exchange to the other will get your funds locked since there will be no message attachment.