My family took a voluntary bump departing from Seattle, after our Alaskan cruise, this summer. We received $600 in vouchers for the three of us, and they must be used within one year of issuance. We had initially been booked with a connection in Phoneix before arriving at our Minneapolis destination. America West put us on a direct NWA flight instead, and we arrived home several hours earlier than the flight we had initially booked. It was sweet!
On our last trip to WDW, we flew Air Tran. When we arrived in ATL for our connection to MCO, Air Tran was overbooked by 12 for our last leg and were looking for volunteers to bump. I sooo wanted to take the bump, as they were up to offering 3 vouchers for round trip travel per person for doing so. My DH and DS were so darned anxious to get to WDW that they refused to bump. I still shame them any chance I can get for that poor decision!
One word of caution, if you decide to bump, there is a chance your luggage may not arrive when you do. It could also arrive before you do, whcih wouldn't be a problem. In our case above, our luggage was delivered by NWA, via courier, the following morning. No big deal because our trip was done and I had a houseful of clothes and toiletries at home. If take a bump, it might not be as convenient if you are missing your luggage for a day or so at your vacation destination.
For the OP, I would suggest packing a carry on or two that has your basic toiletries, your PJ's, a change of day time clothing and maybe your swimsuits. That way, if a bump is offered and your luggage does not arrive to MCO when you do, it won't be such an inconvenience.