Answer by fiat.
To directly respond to the Original Post: you want to avoid questions that can only be answered by fiat.
This wording is supported by several examples of "(noun) by fiat" or "(verb) by fiat", meaning justified by authority or arbitrary order, as opposed to logic or morality.
You get an all-powerful magical creator with attributes that defy basic logic by fiat. We get... a rock. -Aspie, whywontgodhealamputees.com
Obama’s bombshell amnesty-by-fiat is a subversion of straightforward immigration law. -Charles Krauthammer, Washington Post
Applying a different rule may result in a different result, but both rules are right by fiat, because they define what they purport to represent. - G. Scott Acton, University of California, San Francisco
Measurements can be either (a) made when confirmed empirical theories may be used to support their existence; or (b) made by fiat, based on arbitrary definition. -Ahmed Riahi Belkaoui, Accounting Theory
While the original post is looking for one word, and @Village's bounty also looks for the word, brevity has its limits. No single word provided here captures that this answering strategy has a brutish quality lacking in reason or moral force. Any discussion of avoidance should use a multi-word phrase that includes "by fiat".
And in final support of this phrasing, I offer that it is the best damn answer here because I say so.