I have asked via mail to Richard Carrier about what he thinks about Dale Martin's answer to Fredriksen. The answer:
I essentially debate his overall theory (just not this specific claim) in the hands of Bermejo-Rubio, which debate exists only in Italian at the moment though I will eventually get around to publishing an English version, but the key part is already in Jesus from Outer Space (the chapter on plausible Jesus replicates a summary of my debate with Bermejo-Rubio).
Like almost all scholars intent on this kind of thing, Martin is not even considering alternative hypotheses, much less comparing them in evidential merit. This is all just one giant possibiliter fallacy, starting with an assertion of what is possible, handwaving for several pages, and ending up with that possibility magically having become a probability. It’s simply not logically valid. Even his rebuttal is just apologetic rather than empirical (he is trying to make problems go away, rather than actually test his hypothesis empirically to a probability; this is exactly the move of Bermejo-Rubio).
Martin's theory fails to explain a lot of evidence (the absence of any idea of this in Paul, Hebrews, esp. Heb. 9 where it absolutely would have appeared if true, 1 Clement, 1 Peter, or any pre-Markan text; and the fact that Mark constructs this story out of information from Paul and outright states his intent to communicate by allegory rather than literally, and clearly intends this claim about the temple to be a metaphor for resurrection misunderstood by the elite, as a common theme of the elite, even the Disciples, never correctly understanding anything; and the fact that Mark is responding to the destruction of the temple and in fact justifying it and even having Jesus explicitly predict it, per the fig tree narrative and Mark 13, which demonstrates the opposite of embarrassment at this; and so on). Martin is acting like a literalist, rather than understanding why and how mythic narratives get made.
See the alternative and why it makes more sense of the evidence here:
https://www.richardcarrier.info/archives/16428#examples
With background here:
https://www.richardcarrier.info/archives/15934
(There are also problems historically; e.g. Martin seems unaware of the fact that his imagined law against weapons in cities is logistically impossible; people need them on journeys; so where do they store them if they can’t take them home? There was no such thing as lockers outside the city walls. Likewise, his attempt to rebut Fredriksen on the meaning of machaira is all possibiliter, no probabiliter: her point is that the term is ambiguous, commonly referring to an ordinary slaughter knife, which cannot have been outlawed in cities; he responds by simply agreeing with her it can mean either, and then handwaving that into somehow making his reading probable again. And so on.)
Indeed Carrier makes a good point in reading Mark's "false witnesses" and the Fourth Gospel as being basically on the same page about Jesus being misinterpreted by idiotic outsiders about what he really meant by "destruction of the temple". In addition, how could Mark be embarrassed by a Jesus destroyer of the temple if the same parable of the fig tree talks about a Jesus anti-temple?
Carrier refers to Paul and Hebrews as evidence for the his case but I have ceased to see both them as pre-marcionite letters (basically I follow Turmel there).
About the impossibility of lookers at the gates of a city for collecting the swords of the visitors, I think that it is far from being true during a holyday.
Frankly I am a bit disappointed by the fact that neither Carrier nor Kirby seem to like the Dale Martin's
counter-argument that "what Paul ‘joined’ was no longer an anti-temple movement" and that it is the reason why in second century it was not more a question.
The evidence which has come down to us is confusing, contradictory, and doesn't fit into any one nice, neat, coherent theory or theology. 
