The evidence is already given. Segwit creates a triple-classed asset. And that this is by definition a lack of fungibility.
I will pay you 10% under market for all your segwit tainted coins.
Might need to do it in batches.
No?
Thanks for the (disingenuous) offer, but I don't have any Segwit tainted coins.
Not disingenuous. I would buy every single last satoshi.
OK. Sorry for the mischaracterization.
Too bad for me you have none to sell. But I am glad for you that the coins you have you perceive to be more valuable than ones that have touched segwit addresses.
Thanks.
I see the idea that segwit is harming fungibility as being equivalent to the letter above the left serial number on US treasury notes damaging the fungibility of USD.
Well, first, the vast majority of USD exists only in digital form. Such USD has no serial numbers or such letters. As for the small faction of USD in physical form, the letter of which you speak is a discernible characteristic. However, such letter has no operational consequence. This is quite unlike the three segwit classes, each of which implement differing security models. While the letter of which you speak is a fungibility hole, it is of a much weaker variety than Segwit's three classes.
As a snarky aside, why the cliche'd request for 'small unmarked bills'? What of bills marked by the exploding dye pack?
Unless some sort of segwit Armageddon comes (as I understand you believe is possible) it will be a laughably insignificant percentage of users who give a frack whether their bitcoin has ever touched an address starting with a 3.
As I sad, it is legitimate to argue over the significance of the effects of these characteristics.
In fact, talking about bitcoin fungibility and taint and worrying about segwit is silly.
Well, in this conversation I am not so much concerned with taint, as much as the differing security models implemented for each of the three classes created by Segwit.
But I am happy to agree to disagree.