The warnings don’t help when people’s curiosity (morbid, compulsive, or otherwise) has not been counteracted by learned experience (or tools via therapy) that they don’t like it or it doesn’t help them.
The warnings are generally not generic (aka ‘bad stuff here’), they’re usually quite descriptive of what category it covers. Far more than a NSFL warning for sure!
If someone keeps going, it’s not because they did so accidentally. They either thought it was going to be fine and they could handle it (and most can), or couldn’t stop themselves even if they knew it was going to be bad.