In Fetish Locator I think it's mostly for the NTR fetish. While getting the cage is unavoidable there are two options: the NTR cage and the LC cage. The NTR cage has obvious results of getting NTR'd. The LC, or Love Conquers Cage (i think i just threw up in my mouth a little), results in a rimjob and you can get the cage off afterwards. Both sides of it, as well as the scene leading up to it, were poorly handled/written IMO but then again masculine bodies being submissive isn't my thing.
I would put it under the Medium category since you have the option of getting rid of it fairly quickly.