You can leave a message on a borrower's account so that when their account is accessed in circulate, the message flashes up on screen.
From within the circulate module, load the borrower record that you wish to add the message to.
Click the 'Message...' button and the message box will open.
Type a message into the box and click 'Save'.
Next time the account is accessed in circulate, the message will appear automatically.
To stop a borrower message from appearing, remove all text in the message box (or click 'Erase All') and click 'Save'.