Well, to be an example of the "Accident" Fallacy, there would have to be a preceding line of reasoning (which isn't there): "Andrew, Robert, and Charles are Scotsman; Andrew, Robert, and Charles don't put syrup on their haggis. Therefore, No Scotsman puts syrup on his haggis.....
But in the "No True Scotsman," the assertion is originally made gratuitously, hence it isn't the "Accident Fallacy".
I still believe it's a combination of equivocation ("Scotsman" is quickly redefined as "true Scotsman" to avoid refutation, which is clearly an example of equivocation) and petitio principii (one assumes that no real Scotsman wouls put syrup on his haggis in order to justify the equivocation of who is, or is not, a "Scotsman."
Yeah. In my (admittedly sketchy) example I omitted the phrase which is usually understood in all blowhard declarations: "In my experience ..." which would have salvaged the situation; but still, your formulation is more rigorous.
But in the "No True Scotsman," the assertion is originally made gratuitously, hence it isn't the "Accident Fallacy".
No. I think "no true Scotsman" usually asserted as a hasty retreat from the original, all-inclusive claim ("no Scotsman"), once the original claim has been rebutted with a counter-example. Sort of a moving of the goalposts.
I still believe it's a combination of equivocation ("Scotsman" is quickly redefined as "true Scotsman" to avoid refutation, which is clearly an example of equivocation) and petitio principii (one assumes that no real Scotsman woul[d] put syrup on his haggis in order to justify the equivocation of who is, or is not, a "Scotsman."
Continue to contemplate, grasshopper.