Musashi's actually a little impressed, she'll give the movie that much. Somehow, they stumbled into an accurate portrayal of Kojiro's most famous technique. "No, that's about right. I've seen it used before." She replies. "Well, gotta give them that much. Kojiro really did get to be so good with a sword he invented a technique that broke reality a little when he used it. But, that's why he qualifies as a Heroic Spirit, after all. We've all got a big move, or weapon, or piece of gear like that. They're called Noble Phantasms. Like our trump cards, ne? But it's a double-edged sword because using one generally gives away your identity. And once you know who a Servant actually is, it becomes easier to plan around them. If you know their story, of course." But who doesn't have access to the internet, these days?

And it's not like Musashi ever tries particularly hard to hide her identity, though admittedly Iori-kun showing up so early into the Waxing Moon Ritual and recognizing her kind of made it irrelevant anyway.