I found a path where it is possible to never ask Wooh about the United Detective Association, and it is impossible to get the piece of evidence that it never existed. Even trying to restart before the final encounter, you can't ask anyone about the evidence, so you have to restart. The weird part is that the deduction still shows up, and still allows you to make decisions, but the correct answer is not an option.
 "Porkin Hell"){kind=icon}
 "ZS Dead Detective - Rats in a hole"){kind=icon}
 "Super Karoshi"){kind=icon}
In your Porkin Kong Inbox there is a magic scroll! Porkin YEEEEEAAAAAAAAH!