SMF - Terminal B (Alaska Airlines) yesterday - "We STRONGLY encourage EVERYONE to remove their shoes and pass them through the x-ray machine."
Since I walked through Terminal B (United) 3 days ago with the exact same shoes and no problem I walked through with them on at the Alaska checkpoint. Bingo! We have a winner! Off to secondary with you, citizen!
This afternoon at SEA, "N" gate checkpoint. Same shoes - I walk through with no problems.
By the way, SEA's security lines weren't bad today at "N" but it looked like a zoo over at "C"/"D".