What if it IS what my character would do?

[NichG]

Yes, sometimes.

But not in the scenario I described.

In this scenario, the GM made design to change the rules of engagement for the campaign midway through while giving neither hints in-game or statements in real life that the rules had changed. The player who continued to act the way they acted the entire game with no complaints bears no responsibility for the fallout. It s not like he can read the GM's mind.

If you make a character with an extreme button and are told its okay, but then the GM creates a situation where it will absolutely not be okay, you blindly take the action, and no one says anything at the time but complains later, then sure, you're blameless.

But if the GM or another player says 'wait, in this case that's going to cause real problems, please do something else here' and you say 'no, I refuse to back down, its what my character would do' then you had awareness that it would be a problem, a chance to back down or behave differently, but refused. In which case, yes, you are to blame, even if the GM also is to blame. And in that case I'd say that would be far worse than what the GM did. What the GM did there could be an honest mistake, but actively refusing to work with the rest of the table to find an appropriate resolution is overt and intentional.