I've never experienced that but believe it. It's fascinating how Saturdays there don't have the same peak-time traffic situations as in big U.S.ski cities like Denver and SLC. Over the past 20 years, virtually all of my nonstop arrivals to Zurich, Geneva, and (last season) Milan have been on Saturdays -- I land on an early morning flight, am usually out of the airport by 9:30 am, never hit traffic, and am booting up by late morning.
Hah, that's the last year I bought the full version of that book. An excellent primer for Euro skiing; however, as I've noted before, you learn as much or more about British culture and preferences as you do about skiing in the Alps.
I have seen some returns to Zurich on a Sunday from Chur (Davos, Arosa, Flims, etc)....20 km of backup? Also, leaving Geneva on a Friday out toward PoS, Verbier, Zermatt, Villars, etc .... a very similar backup along lake Geneva. Much worse than anything I ever witnessed on I-93 coming in/out of Boston on a mid-winter weekend.
I have bought the newer versions of WtoSS by country: France, Italy, and Austria. I think they are pretty good. They give a decent overview and will talk about off-piste. Also, their lodging hints and restaurant recs are useful too. But they definitely just cover the mid-to-large resorts.