Funny that it took me until now to realize this (maybe all the experts here already know). But if you book 2 one way tickets on alaskaair.com instead of 1 round-trip ticket, you get two 1000 mile bonuses instead of just one. And the fares add up to be the same as the roundtrip.

Is there any downside to doing this? It's not a lot of extra miles, but if you're taking a lot of short-haul trips over the course of a year, it could mean 1-2 extra free tickets, easily.