Anybody who has kids knows that for some "Why...?" questions the only answer is "because".

That said, a friend of mine HAS checked in for a flight not flown, just to get the miles (he also had a plausible excuse why he hadn't flown), and this worked. International would be different, of course. Apparently they rarely check seats against tickets, and even then there's a small leeway before they go to further trouble dealing with it.

In fact, Old Gold, he has checked in for both legs of a same-day round-trip and gotten back in his car; the miles (and the all-important bonus that was the reason for this lunacy) posted just fine. So he would have pocketed the $400 and gone sightseeing in Phoenix. Or bought a one-way back to Tucson. But changing the existing return to Tucson wouldn't have been an option - it would have alerted the airlines to the subterfuge.

Basically, the mileage programs are a game: they make the rules, and we play the game to win. But we have to stay within their rules.

As for the grammar issues here, I'll grant that I don't like people using u and r instead of typing out all those extra letters, but there are more important things to get upset about such as people who insist on wearing white before easter.