Here's two really minor ones in Infinite Stratos 2 -
In episode #4, around the 13-min. point, a girl is tied up with webbing. (These are "high-tech" webs from a spider mecha, not a supernatural spider.)
In episode #7, around the 5:30 point, in an anime-within-the-anime a girl is seen strapped to a table (and menaced by a goofy-looking villain).
Anime Sightings Old and New - Infinite Stratos 2nd season
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