I don't think it would be difficult at all. I can count over 10 of my friends who have in excess of 150,000 miles that have no idea that there is a black market for selling miles and wouldn't know if it was right or wrong to do it.

Some other poster mentioned the same thing, they earned the miles so as far as they are concerned they can do what they want with them.

If you apply a common sense approach to it, which most people that don't know about sellings miles would, the above statement would probably be taken by most.