Of course one should be held accountable, that's why I put in a safety report.
It was not an immediate safety concern for the flight but nevertheless a report should always be submitted to catch emerging trends so possible procedural changes can be made accordingly. It's called good airmanship.
It's totally unreasonable to expect the cabin crew to understand our flight manual. I actively ask the cabin crew to speak up and not be afraid of questioning something that happened during flight, no matter how small it may seem. However it is insulting when I provide an answer to their query only then be second guessed.
Now I will make an effort provide evidence to cabin crew with questions on procedure, when I can, by showing the appropriate section of our manual.
And yes the same is true for some captains who make it very difficult for cabin crew to approach them and query them, only to be scolded. I try my best to use good CRM skills and the same should apply to cabin crew, I know a lot of cabin crew with very good CRM and communication skills, they are an absolute joy to fly with.
I suppose I do work for a relatively small airline and those cabin crew who are a little average get weeded out of the group as they progress to larger airlines.