Regarding Josh's take on the Saberspark situation and in particular verbal/nonverbal consent: I do agree, but it's

as hell to assume any of these turbo-autist internet guys who get accused of rape have the social acumen to pick up on non-verbal queues (be those consenting or nonconsenting).
Almost every time something like this comes up, it's the exact same thing: a 20-something nerdy autistic guy gets Internet famous and suddenly has a lot of positive attention, including from young women, which they've probably never had before. Then, just as Josh said, they don't want to settle down with the first teenage fan girl that comes back to their hotel room with them, so they just string them along and have casual sex with as many of them as possible without making it clear that they aren't interested in a relationship. The girls go along with it because even though they're not actually comfortable with casual sex, they think if they put out they'll get a relationship out of it. They also assume that if they give enough nonverbal signals that they aren't comfortable, the guy will notice it and back off, but since they're horny and autistic, they don't. It's stupid, but we're usually talking about girls in their late teens who aren't exactly well known for good decision making.
Additionally, from a female perspective, it's hard to outright say "no" or putting up resistance in a situation like that when you're with a guy that you really like. Beyond just the matter of "if I give him what he wants, he'll reward me with a relationship," there's the concern of being seen as a boring prude and then losing the attention he's giving you. On top of that, there's always the small chance that he could react poorly - you never really know, so it's safer to just go along with it sometimes.
Contrast this kind of thing with what happened to Dan from Game Grumps. He's a guy who from my understanding has had a lot of casual sex even before he became Internet famous, and so when a fangirl approached him, he made it perfectly clear that he was only interested in casual sex and got her to explicitly consent to having casual sex. His cancellation didn't work because it was a grown woman who agreed to the groupie treatment and then later regretted being treated like a groupie.