No, the default setting for everything that uses your reaction should be "ask". Some other reactions are currently set to "always activate" when you level up and to me it's quite annoying when they get triggered and prevent me from doing opportunity attacks.
In my view the game should simply retain your setting on level up so you don’t have to keep resetting.
Personally I think the default for reactions should be active, but we should get a tutorial the first time we get access to a configurable reaction letting us know our options. I’d probably set all reactions to ask myself now, but thinking back to what I’d find most accessible as a new player with a ton of other stuff to get my head around, then on by default seems a better starting place. Or even on by default but a setting in options to configure the default if we wish.
