Nope.Things change during gameplay, though. A druid might be willing to put on metal armor in order to save a forest or something else important to the character. When choosing druid, the player does not agree to let the character's character die in order to maintain no armor. If the only option to stay true to the character is to don metal armor briefly, the player can have his druid do that. A DM who says no doesn't deserve the job.
**if** the gm setup a druid trap situation so that the only way to survive was for the dtuidnplayer to violate the rule they agreed to play, then thats on the GM. His failing was sgreringbthst druids in this campaign will not wear nrtsl armor and then setting up an "'only way" trap against that. Thsts the GM violating the rule.
On the other hand, if there were/are multiple options and due to failure or choices the players have driven thfmsrlve to " no opyionsvthry like better than violating the rules" then thsts on them and they cannot break the rule, any more than if it was a case of PvP or die.
So, hey, it noilscfoen to very simple, you cannot violate the rules you agree to play by. So if the GM forces you to a no-win its z no-win. If you work yourself into a no-win, its a no-win.
"Hey, we cannot win this fight unless I have zanother fireball but I used sll my slots already?"
What a tyrant.