Return By Date ... What's it for?

 Good day all.        I'm reviewing the field Return By Date in depot and understand that this is a required field for any transaction types that require a return.  My question is does the information provided in this field drive any additional functionality.  For example, if a unit was replaced on an adv. exchange and the return usit is not returned by the 'Return By Date' does anything happen in the system?  It would be great if it billed the customer for the replacement if the replaced unit was not returned in time, etc.   Just trying to figure out what,