Trigger refresh/update smart playlists in iTunes using Applescript?
Update Smart Playlist entry only resides in contextual menu; applescript cannot access that. There are two work-arounds I can think of: 1. BTT: hover over the playlist and invoke a combo right-click -> u -> return. Or:

tell application "System Events" to tell application process "iTunes"
    set frontmost to true
    repeat 2 times
        tell menu item "Edit Smart Playlist" of menu "File" of menu bar 1 to perform action "AXPress"
        tell checkbox "Live updating" of window 1 to perform action "AXPress"
        tell button "OK" of window 1 to perform action "AXPress"
    end repeat
end tell