Like someone else posted, I rarely have problems with seats changing. When they do change, 100% of the time I've been able to tie to something specific, like an aircraft swap that changes layout. (Side hint: never book row 4 in First since some aircraft don't have 4 First rows and that's problematic with a last minute swap!). I often use I often use flightstats.com to check on aircraft changes (look for tail number changes in the log).

Since you have a recent example of an unexpected and unsatisfactory seat change, I'd suggest submitting feedback to AlaskaListens.com and include your confirmation code. They seem to pay lots of attention to that and answer you specifically if you ask for a reply.