from personal experience it goes off and on. i'm into both s&m. i like getting spanked among things, as long as i get to do whatever i want. just don't EVER blindfold me!
she probably is just not comfortable if she always goes for the spanking when drunk, asking for that kinda stuff otherwise cos she is nervous about how you might feel about it. it seems like you're into some pretty straight forward sex which might be a detterent for her.