I'll bet most of the airlines' crankiness about back-to-back goes to the days when Sat. night stays meant huge differences in fares. It was a no-brainer for M-to-F commuters to use them, with great revenue implications. The solution, of course, was two different airlines/programs, to the ultimate revenue detriment of the preferred carrier. But that was a dilemma they had to resolve they way they did/do.

My son, who somehow has become a miles junky, independently derived the b-2-b concept, using two weekend fares, as a ploy to circumvent his Mother's denial of MRunning overnight. After posing the "strategy" to the MR forum, and having him read the responses, for once both his Mother and I got what we wanted: an uncontested No.