This should really be moved to Travel Security- look for it under "Travel & Dining" section.

That said, I see no difference between East Coast & West Coast- they're both inconsistent. I fly SEA to EWR about once a month, and SEA to SAN/BOS/DTW quite often, and I get asked to take my shoes off maybe 60% of the time at each airport. I usually travel wearing car shoe mary janes- very thin sole, but at least they slip on/off easily. As far as I can tell, it just depends on what mood the screener is in that day.