True, and I would expand that statement to say that all businesses are constantly improving their data mining ability, not just the airlines. Law enforcement, grocery store loyalty programs and online sellers come to mind immediately. Just think: you are constantly hearing about how Google refines its search engine algorithm. If Google can do it, so can an airline.

I am a database administrator, so I know what I'm talking about. I do not work for an airline, but instead work for a company that has similar complexities in terms of volume. I know I can write queries to flush out abnormal patterns of activity. That's my job. It doesn't take a platoon of dataminers. It just takes one programmer who is good at designing queries.

Worth reiterating that there is a big difference between mileage brokers, which I would not touch, and legitimate consolidators / bucket shops, which are OK, although the ticket you buy from them may not earn miles.

I agree with this statement..

If you are making a payment for purchase of miles straight up.. that's likely against T&C, and originating source is non transferable..

That means you might be stuck with useless and unusable miles.. and a challenging time to try and get your money back.. imo.. not worth the hassle.

Also worth noting that if you buy from other than a carrier, your contract is with the third-party vendor. If everything goes as planned, there is no difference. Your BP and seat look the same. But, if something goes wrong, whether MX, WX or other, you are at the mercy of the carrier for immediate assistance.