This "trick" does not depend on paper or e-ticket types. It's to accomodate TA mistakes, ticket printer jams, etc., and is not supposed to be used to change or cancel tickets. Our company TA does it from time to time for us, but has warned us that if it happens to much, the agency can be audited by the airline. This is not a "good thing."

'Course, I don't use the TA, so it makes no nevermind to me.