I just made this account to comment here.
I see that most of the people here don't see the point of having a warning because there are so few complaints. But that is because sexual assault victims rarely complain. We get bullied if we do.
On the rare occasion that I mention my experience, I get told that "that's hot" or "stop being a little whiner baby, it's just sex". Well that's the only sex I have ever had. I've tried since then but I get panic attacks and it just doesn't work.
I still get horny though. I watch anime and play adult games to feel some of the emotional side of sexuality and I have toys that help with the physical.
A lot of games on here have rape. I skip those. Some have lesser rapey stuff and I can usually see it coming and decide whether or not I want to keep playing. If I do, I steel myself and power through it.
Serenity springs it on you. You go from losing your virginity to your childhood friend to the next scene of being a piece of meat with no control over what is happening to you.
Both scenes made me cry. The first one because I wish that's how my first time was. And the second because that is how my first time was (poetic license, the specifics of what happened to me were very different). Those two scenes right next to each other, just wow. Sadist.
You can't base you're opinion by how the scene ends. The panic attack starts when the scene starts. You are filled with fear and you have no idea how the scene will play out. You freeze. "Should I stop now and have this moment of dread paused in my psyche OR should I keep playing and hope that I get saved? How bad will it be if I don't get saved?"
If it had a warning saying "by the way, you need to take a moment. Bask in the joy of the previous scene. Then go way for a while. Smack yourself in the face. Brace yourself for some less than consensual sexual interactions." It wouldn't have hit me so hard.
I hate spoilers as much as the next person. But for this kind of stuff it really helps to know what happens, before it happens. Especially penetration. Or any unwanted physical contact with the genitals. That's when I start freaking out.
EDIT*
Oh, I was just thinking. Maybe adding a "play though it" or "text wall" option would help for sensitive people. I really try to connect to the MC on an emotional level. And seeing everything POV makes me feel like I am in their shoes, experiencing what they are going through.
Having a disconnected third person account of what happens in a text wall would allow you to keep telling the story while sensitive players can pull back emotionally from the character.
Hmm... actually that just makes it sound like I need therapy.