The way I see it - its all about levels of stimulus; an experience generates x quantity of stimulus to a person who has a stimulus tolerance of y.
if a person with low stimulus tolerance undergoes an experience that generates greater levels of stimulus than they are capable of handling, they will be overwhelmed in a very unpleasant way - e.g. a neurotic agorophobe with vertigo riding a rollercoaster would most likely be a gibbering wreck.
The same rollercoaster rode by a person whos stimulus tolerance is just bordering on the stimulus level of the experience would have undergone the same action, but they would have had a great time.
Another person whos stimulus tolerance was way above the rollercoaster, would have also undergone the same action but with the result of being bored and underwhelmed
So the problem is, that while the stimulus level of an activity is (somewhat) predictable, the stimulus tolerances or individual psychological triggers of the person undergoing the activity is not, and as such I reason that while we as the creators of these activities are aware of the nature of what we are creating (a scary game, a psychologically mindf**king game, a heart-racing adrenaline ride of a game etc etc), we have no choice but to simply judge whether or not our material is “suitable for all audiences” and ensure that stimulus levels are kept to a constant, steady pace or declare our material “suitable only for adults”, by this implying consenting adults of a right mind, and trust that they have the good sense to know what is beyond what they find comfortable.
In short - if you go into a curry house and order too hot a curry, you burn your mouth. If you go see a film that is too scary, you will wet yourself. They might say the curry is hot - they might say the film is scary, but it is at the customers discretion as to whether they want to experience it.