Indeed. EK just rang a friend of mine who is over from London, they are supposed to fly out on EK29 tomorrow and were asked to volunteer to be re-booked on EK9 to LGW instead with a free ticket. They weren't sure though if the offer was for a one-way or a return nor of how they will actually collect the comp ticket voucher at the airport.
A while ago I was voluntarily offloaded when I was booked in F on BKK to DXB, and the operating aircraft was changed to two class. They offered me a seat in business on that flight, but in exchange for me agreeing to wait for 4 hours for the next service in F, they gave me a room at the Novotel with dinner, and a free return ticket in F for UK to BKK, valid for 1 year. They also sorted the connection in DXB. It sounded too good to be true, but worked fine although as I recall the free flights had to be booked in the reward category. The voucher was issued in BKK.