I heard this one propsed a good while ago now on TV news in the UK.
As much as I think Ryanair's way of doing things is fairly good, this one just ain't gonna work if you ask me...
Everyone I know will just pile onto the aircraft for the free flight, and read a newspaper instead of wasting money on slot machines, which would probably replace the lifejacket under your seat if MO'L could get away with it!