I always wonder this same thing with some of the more out-there requests, in the past, too.
I've been wrong at times as well though.
ETA; Also there are guys (usually the internet Doms) who assume that because they've interacted w a model who shares a humiliation fetish w them in the past, all models or all submissive models do. That's a super unfair assumption/ over generalization of them to make, when it literally takes 2 seconds to ask someone directly; "are you into humiliation/ do you have a humiliation fetish yourself?"
I always ask all new subs that, and the majority of them answer "No" to that question. And their behavior and interactions are consistent w that i.e. many know their own limits and what they are into and are fully able to communicate that clearly.