Trigger warnings...

There was recently a short drama series on TV that I really wanted to watch and having the time, settled down for a binge session...at the start of one episode, there was a 'trigger warning' which basically gave away a crucial part of the plot although taking the storyline as a whole, you could see what was likely to occur.
Then a couple of nights later, I started to watch a documentary that was about a famous criminal case and again 'trigger warnings'.
AIBU to think that if you are going to watch something of that nature do you really need a warning?
I do appreciate that certain films / programmes may have a scene that can come out of the blue and in those cases perhaps a warning could be viewed as important but otherwise....