My theory: if you need trigger warnings, you need to stay off the internet. Diagnosed PTSD sufferers function in life without trigger warnings; they learn to recognize what might trigger them or what is triggering them, and they react accordingly.
Are there any real sufferers of PTSD who are triggered by text? If so, wouldn't the trigger warning itself be triggering?
ETA: For some context:
When “Trigger Warning” Lost All Its Meaning | The Awl
The Illusion Of Safety/The Safety Of Illusion - The Rumpus.net