Recently my seat opponent was a milage broker.

We had a very interesting conversation. Apparently he buys miles and re-sells them as business class and first class tickets.

He mentioned that some airlines never question the buyer at check in where some other airlines almost always question.

Also it was intersting that he was more interested in accounts with low milage so he would sell only one ticket from that account at a time. He then stated that he would encourage people wanting to sell AMEX/Diners miles to open multiple accounts at the same airline.

What was most intersting was that he had a wealth of 'street knowledge' on how to get from XXX to YYY and in what airline before even making a call.

For example, he stated Qantas tickets are impossible to get, where JAL tickets are relatively easy.