My understanding is that trigger warnings, in terms of helping people avoid reminders of trauma, are at best superfluous and at worst actually increase anxiety and negative emotional associations. Or at least, that's what I've gathered from reading up on several recent studies investigating them:
I remember, way back when in ancient times (i.e. the 1980's), when they started putting warning labels on albums with "questionable content." I know that myself and my circle of friends would almost always buy an album if it had one of those stickers on it.