>>60721
>Things like rape should be allowed for players who wish to partake in it, though I don't know how exactly you could keep it from happening to people who really aren't into that sort of thing.
The simple method would be to just do what >>60748 said, and just have players who are interested have a tag or some other indicator.
The more complex method would be to have social stratification which sees those certain characters less as people and more as property or some other less-than-human moniker. It's not rape if the law says they don't have the rights to their own bodies. Players could opt to be these people by being debtors, criminals, outlaws, unnaturalized citizentry, spoils of war, penitent lawbreakers, or just born into the wrong place in society/caste/have the wrong mutations.
Heck, depending on who and what and why, people might WANT to be treated as property. Being a slave means you'll probably get fed, even if it is gruel, and you'll have a roof over your head and maybe even a few creature comforts. A slave is an investment, and the master is going to want to get what he is paying for.
You could even play around with this a bit in interpersonal and cultural politics. Some might say that a slave should be treated well and a well-educated, un-abused slave is an indicator of wealth, power, and benificence. Others might say that they're lower than the dirt they stand on anyway, and who cares how they're treated? They're appliances, tools, receptacles for your lust. Fuck 'em.
You could even get MORE in-depth with it: By fucking with a wealthy/powerful person's slave, then you're basically screwing with someone's property. It's vandalism, and you might get your comeuppance. On the other hand, if you get away with it, then ha-ha! he couldn't keep his property safe, and thus does the master lose respect among his peers.
In a post-apocalypse or sci-fi settings there'd be an abundance of ways to mark such people: Shock collars, tattoos, data chips, the old-fashioned branding mark, a certain style of clothes (or lack thereof!), maybe even a genetic modification like eye-color. I don't know very much about Fallout and other post-apocalyptica, I don't especially like that kind of setting, but I like where this thread is going and I wanted to contribute to it.
I feel like I should make a joke somewhere in here. Something about rape culture etc. etc. but I'm not feeling imaginative at present.