Yeah, if I had a dime (or 100 miles) for every time a coworker or friend told me "I don't fly airline XYZ often enough to get anything."

I made a huge point of this when a good friend came out to visit last year, on a NW ticket. She didn't have any FF#s at all, so I signed her up for NW WP. I also made sure to tell her that she should use the same number when flying on Delta or Continental.

Sure enough, she just made a trip to NJ on CO and proudly told me she signed up for OnePass! Brilliant (not). People either don't sign up, or they spread their miles all over even within an alliance.

Horse. Water. Drink.

Amazingly, these folks are sometimes the same people who'll be seriously into store rebates and coupon deals, but don't get it about FF and Hotel loyalty programs.