If someone liked images of solo bondage or non explicit bondage, they could blacklist:

"bondage" + "rating:e"
"bondage" + "male"
"bondage" + "censored"
"bondage" + "sex"

If they didn't like bondage at all, they could do "bondage" by itself.

Sometimes you have to think a little and get creative with the combos.

Edit: It's just funny to me that you consider that extreme.