Guess TLC got what it wanted - people to watch the show. How misleading though.
I am not a fan of previews, especially when it is for a movie and when you see the movie, the big moment has been spoiled by the preview. OR if the previews were the only good part of the movie.... so disappointing.
The teasers for regular shows get old, you practically know them by heart by the time the show airs (especially on Disney owned stations, guess they are too cheap to make additional commercials).