No matter how many seats you purchase for yourself, other persons, your stuffed animals, your musical instrument, or other posessions, no airline that I know of intentionally awards more miles to you than a single seat would earn. Doing so is against most airline's published policies, and most work hard to try to thwart people from doing this.

Why? I don't know. There have been NUMEROUS times I could have purchased a cheap seat, had more room, added to their revenue, and the extra elite-qualifying miles would have pushed me into buying additional seat(s).

Sure would make mileage runs a lot easier and faster, too!

In fact, three seats together, so I could lay down from LHR-SEA at deep discount economy prices, each earning elite-qualifying miles would be SUCH a no-brainer! And they PROBABLY could even trim some of those HORRIBLE taxes too, if I didn't put other people in them.