I generally accept an undo when presented with it.
But I generally also find it an unwelcome double dilemma: first, “is it really fair to accept it?” (especially when it is not a blatant misclick) , and second later on “OK so I accepted his, now will I ask for one in a case where I need it?”.
And I’ve concluded this would all be a non-issue if the game was set up at the start as a “no-undo” game, with no undo button showing at all.
Note that the context of this is correspondence play, where a true misclick is pretty rare.
I’m thinking “how about we have an option to set up games as no-undo”… so people could decide they simply don’t want these questions in their games…