FWIW, this is sort of my standard practice.
Most of my travel is last-minute with an unsure return date. (50/50 domestic/international).
I'll book a refundable ticket, then when I'm certain of my return date I'll call the DM line and change my return flight to non-refundable, and the fare difference is refunded for the return flight.
I've even made this change at the airport just prior to checking in for my flight home. Saves the company a bit of money.