I imagine doing it once would start me down a very slippery slope. I pretty much never missed a day in HS unless I was really sick. In college, any skipping I've done has been more out of laziness (usually coupled with the class being at a god-awful early hour like 9 or 10am, lol) than SA.
I can definitely understand why some people with SA would do it from time to time, but I'd be very worried about it quickly leading down a path to more and more withdrawal from necessarily life experiences. Then again, I have approximately zero will power and self-control, so I've come to recognize the types of things I have to keep myself from doing even once.