If you have a different web site that explains it better please provide it.  If you can show text where Mr. Crane gave a clear example even better. I have searched for documentation on what he said, I can't find it.  An appeal to authority is a logical fallacy for a reason, an appeal to an authority that no one else can find doubly so.
		
		
	 
"Appeal to authority" is only a fallacy if the authority is 
unsubstantiated. AKA, if I were to site Joseph Schmoe on the subject of double jeopardy in the United States and whether a mistrial will thus result in functional acquittal (due to the constitutional restriction against double jeopardy) or in a retrial (due to the Supreme Court's stated understanding that the right to not being tried for the same offense requires 
some deference to getting a speedy 
and fair trial), that would be an appeal to authority fallacy.
But if I were to cite Justice Brennan, in 
United States v. Lanza, that would not be an appeal to authority 
fallacy--it would be an appeal to a legitimate authority on the subject, particularly since 
Lanza established that it is 
not double jeopardy to be tried by a state court, and then subsequently tried in federal court, and indeed is the reason we have the "double sovereignty" doctrine in the first place.
Now, obviously that's an unequivocal example since Brennan himself wrote the opinion which established this precedent. But it's not like Luke Crane is some no-context nobody. You may or may not 
like his conclusions. You may find his diction or his style or his approach awesome or terrible or mediocre or whatever else. But let us not pretend that he is an irrelevancy. He is, for all intents and purposes, one of the foremost voices on the study of roleplaying game design. You may argue that his opinions are 
wrong, that's perfectly within your rights. But saying that it's an appeal to authority fallacy to reference his body of work? No. That's not valid. Just because 
you don't accept a person as being an authority, doesn't mean you can then assert anyone 
else doing so is automatically committing a fallacy.
(Nor, it's worth noting, is it valid to conclude that because an argument used a fallacious line of reasoning, it must therefore be 
wrong. That's the fallacy fallacy. "Whales have hair; Mammals have hair; Therefore, whales are mammals" is a fallacious argument, even though the premises 
and the conclusion are all true. It's just that the truth of the conclusion does not 
follow from the truth of the premises.)